Poster presentation, abstracts ()

Poster presentations – ESEAC2014
Posters numbered T# are presented on Thursday 12 June, Posters numbered F# are presented on Friday 13
June.
T1 – T61
T1.
Al-jaber, Nabila, King Said University
Investigation of the chemical contents and the biological activities Achillea fragrantissima
(Forssk)
T2.
Amato, Letizia, Technical University of Denmark
Tailoring the structure and the properties of pyrolysed carbon electrodes
T3.
Ambrosi, Adriano, Nanyang Technological University
Large-scale quantification of CVD graphene surface coverage
T4.
Antiochia, Riccarda, Sapienza University of Rome
Monoenzymatic amperometric biosensor for physostigmine detection based on screen-printed
electrode modified with cobalt phthalocyanine-carbon black nanocomposite
T5.
Azhari, Syaza, UTM
The Use of Ethylenediamine Compounds for Differential Pulse Anodic Stripping
Voltammetric Determination of Copper(II) at a Glassy Carbon Electrode
T6.
Bakmand, Tanya, Technical University of Denmatk
Versatile electrochemical sensor for tissue culturing and sample handling
T7.
Baldo, Maria Antonietta, Ca' Foscari University of Venice
Voltammetric behaviour of ferrocene as probe molecule in olive oils using a phosphoniumbased ionic liquid as electrolyte
T8.
Bandžuchová, Lenka, University of Pardubice
Voltammetric method for rapid and sensitive determination of herbicide triclopyr on bare
boron-doped diamond electrode
T9.
Bavol, Dmytro, Charles University in Prague
Voltammetric determination of cymoxanil and famoxadone in river water and soil
T10.
Ben Mefteh, Wahid, Institut des Sciences Analytiques
An electrochemical gadolinium sensor based on Gold surface functionalized with terpyridine
ligands
T11.
Bernalte, Elena, University of Extremadura
Electroanalytical behaviour of Gallic and Ellagic acid using Graphene modified ScreenPrinted
T12.
Bernalte, Elena, University of Extremadura
Electroanalytical behaviour of Gallic and Ellagic acid using Graphene modified ScreenPrinted Electrodes. Method for the determination of total low oxidation potential phenolic
compounds content in cork boiling waters
T13.
Bóka, Beáta, Eszterházy Károly College
Development of an amperometric glutamic acid biosensor for food analysis
T14.
Bonanni, Alessandra, Nanyang Technological University
Inherently Electroactive Graphene Oxide Nanoplatelets as Labels for Single Nucleotide
Polymorphism Detection
99
T15.
Canali, Chiara, Technical University of Denmark
An innovative EIS based 3D printed conductometer
T16.
Canali, Chiara, Technical University of Denmark
Electrochemical impedance spectroscopy is a versatile technique for new challenges in 3D
cell culture
T17.
Cavanillas, Santiago, University of Barcelona
Parametric Signal Fitting by Gaussian Peak Adjustment methodology for the analysis of the
non-linear voltammetric data
T18.
Caviglia, Claudia, Technical University of Denmark
Real-time monitoring of drug-induced cytotoxicity kinetics using a tailor-made impedance
platform
T19.
Celiesiute, Raimonda, Center for Physical Science and Technology
Electrochemical synthesis and characterisation of poly(folic acid) films
T20.
Čičić, Sandra, University of Zagreb
Influence of structure, interstitial cations, and structural defects on electrocatalytic properties
and stability of Prussian blue-based catalysts for sensor applications
T21.
Dago, Àngela, University of Barcelona
Electrochemical detection at screen-printed electrodes modified with carbon nanotubes for
the analysis of aminothiols in plant samples
T22.
Daniele, Salvatore, Ca' Foscari University of Venice
The use of Platinum Nanoelectrodes for the Detection of Hydrogen Peroxide
T23.
de la Gala, Maria, University of Extremadura
Study of the complexation of Pb(II) with meso-2,3-dimercaptosuccinic acid and 2,3dimercapto-1-propanesulphonic acid using a bismuth-bulk rotating disk electrode
T24.
del Valle, Manel, Autonomous University of Barcelona
Monitoring the photodegradation of pollutant phenolic compounds by means of an electronic
tongue
T25.
Delaney, Aoife, Institute of Technology Tallaght
Design and Fabrication of Printed Electrochemical Immunosensors for Progesterone Testing
– AURO-QUANT
T26.
de-los-Santos-Alvarez, Noemi, University of Oviedo
Synthesis and functionalization of Fe3O4@Au core-shell nanoparticles for the
electrochemical detection of maize mon810
T27.
de-los-Santos-Alvarez, Noemi, University of Oviedo
Ultrasensitive electrochemical aptassay for detection of gluten in food: improving celiac
patients’ safety
T28.
Dossi, Nicolò, University of Udine
Pencil-drawn electrodes for paper-based electrochemical devices
T29.
Draminska, Sylwia, University of Warsaw
Biobattery powered sensor for neurotransmitters
T30.
Eßmann, Vera, Ruhr-University Bochum
Linking glucose oxidation to electrochemiluminescence using bipolar electrochemistry
100
T31.
Esteban-Fernández de Ávila, Berta, Complutense University of Madrid
Multiplexed determination of amino terminal pro-B-type natriuretic peptide and C-reactive
protein cardiac biomarkers in human serum at a disposable electrochemical
magnetoimmunosensor
T32.
Fau, Michal, University of Warsaw
Polypyrrole-Au Nanoparticles Composite as Suitable Platform for DNA Biosensor with EIS
Detection
T33.
Gimenez-Gomez, Pablo A., Barcelona Microelectronics Institute
Development of a bienzymatic amperometric sensor device for the analysis of lactate
T34.
González-Cortés, Araceli, Complutense University of Madrid
Single-walled carbon nanohorns – modified electrodes as immunosensing platforms for the
sensitive determination of fibrinogen in plasma
T35.
Gugala-Fekner, Dorota, Maria Curie Sklodowska University
Influence of adenine on Zn 2+ ions electroreduction in acetate buffer
T36.
Gugala-Fekner, Dorota, Maria Curie Sklodowska University
Adsorption of guanine at the electrode – acetic buffer interface
T37.
Gutiérrez-Capitán, Manuel, Barcelona Microelectronics Institute
Nanocomposite Electrode for the Analysis of Chemical Oxygen Demand in Wastewaters
T38.
Gutiérrez-Capitán, Manuel, Barcelona Microelectronics Institute
Multisensor system based on electrochemical microsensors and data fusion for classifying
grape juices
T39.
Guziejewski, Dariusz, University of Lodz
SW components peak potential separation in estimation of electrode processes kinetics
T40.
Guziejewski, Dariusz, University of Lodz
Amplitude based quasireversible maximum in electrode kinetics determination with square
wave voltammetry
T41.
Guziejewski, Dariusz, University of Lodz
Application of graphene oxide-carbon paste electrode for determination of lead in rainbow
trout’s from Central Europe
T42.
Guziejewski, Dariusz, University of Lodz
Voltammetric quantitative determination of disulfiram in urine and commercial formulations
T43.
Hajkova, Andrea, Charles University in Prague
Voltammetric determination of 2-aminofluoren-9-one and investigation of its interaction with
DNA on a glassy carbon electrode
T44.
Hnida, Katarzyna, Jagiellonian University in Krakow
PPy-HQS composite nanowires for pH sensing application
T45.
Hudak, Orsolya, Eszterhazy Karoly College
Development of glycerol oxidase based biosensor and GC methods for glycerol analysis in
wine samples
T46.
Hudak, Orsolya, Eszterhazy Karoly College
Glutathione peroxidase based amperometric biosensor for glutathione determination
101
T47.
Iffelsberger, Christian, University of Regensburg
High-resolution scanning electrochemical microscopy for the characterisation of thin and
thick film electrode materials
T48.
Iskierko, Zofia, Institute of Physical Chemistry PAS
Early detection of renal disfunctions: development of inosine-imprinted polymer as a
recognition unit in the Extended Gate Field Effect Transistor sensors
T49.
Jarosova, Romana, Charles University in Prague
Chronopotentiometric Determination of Nitrophenols Using Reticulated Vitreous Carbon
Electrode
T50.
Jovanovski, Vasko, National Institute of Chemistry
Porous metal film electrodes for improved electrochemical analysis
T51.
Killard, Tony, University of the West of England
A biosensor for the amperometric determination of high density lipoprotein cholesterol based
on a printed lyotropic surfactant layer
T52.
Killard, Tony, University of the West of England
Printed sensors for the determination of blood ammonia
T53.
Killard, Tony, University of the West of England
A printed cholesterol biosensor based on a novel H2O2 electrocatalyst
T54.
Kiss, András, University of Pécs
Investigation of corrosion protection coatings on AZ63 alloy with SECM
T55.
Kowalczyk, Agata, University of Warsaw
Hydrogel matrix doped with gold nanoparticles and grafted with carboxyl groups for
improved performance of DNA biosensors
T56.
Krejcova, Zuzana, Charles University in Prague
Voltammetric Determination of Nitrofurantoin at Mercury Meniscus Modified Silver Solid
Amalgam Electrode
T57.
Krikstolaityte, Vida, Vilnius University
Mediatorless carbohydrate/oxygen biofuel cells with improved cellobiose dehydrogenase
based bioanode
T58.
Kwasny, Dorota, Technical University of Denmark
Electrochemical detection of chromosome traslocation
T59.
Lamberg, Peter, Malmö University
Direct electron coupling of Humicola insolens cellobiose dehydrogenase by using structurally
similar thiols
T60.
Lenik, Joanna, Maria Curie Sklodowska University
Beta-Cyclodextrin based diclofenac potentiometric sensor
T61.
Lenik, Joanna, Maria Curie Sklodowska University
Solid contact cadmium ion-selective electrode based on ionic liquid and carbon nanotubes
T62.
Li, Xianchan, Chalmers University of Technology
Microelectrode Biosensor for Real-time Measurement of ATP Release from Single Cells
T63.
Lopez, Miguel Angel, University of Alcala
Magnetic beads based immunosensor for fumonisin B1 detection using modified CSPEs
102
T64.
Lopez, Miguel Angel, University of Alcala
Fast and reliable class-selective isoflavone index determination on carbon nanotube presstransferred electrodes using microfluidic chips
T65.
Macikova, Pavla, Palacký University
Amperometric Biosensor Based on Horseradish Peroxidase: Effects of Various Mediators and
Nanoparticles
T66.
Markova, Eva, Palacký University
Anodic oxidation of 2,4,6-tribromophenol in alcohol-aqueous media
T67.
Mason, Marco, Free University of Bozen
Concerted determination of the hydrogen atom and electron transfer capacity of lipid
reducing agents
T68.
Matysiak, Edyta, University of Warsaw
Modification of gold surface with magnetic nanoparticles for preparation of sensitive
hemoglobin biosensor
T69.
Matysik, Frank-Michael, University of Regensburg
Fast capillary electrophoresis in short capillaries with electrochemical detection
T70.
Mika, Jan, Charles University in Prague
New coulometric detector with renewable working material for flow injection analysis and
HPLC
T71.
Montini, Lucia, Technical University of Denmark
Mediated amperometric monitoring of DT-diaphorase induction in cancer cells - tool for
screening phytotherapeutical drugs
T72.
Moo, James Guo Sheng, Nanyang Technological University
Electrodeposited Self-Propelled Microfish Robot for Selective Detection of Pb2+ in Waters
T73.
Moretto, Ligia Maria, Ca' Foscari University of Venice
Electroanalytical applications of pyrolyzed photoresist carbon electrodes in aprotic solvent:
from bilirubin electrochemistry to superoxide electrogeneration
103
Poster presentations – ESEAC2014
Posters numbered T# are presented on Thursday 12 June, Posters numbered F# are presented on Friday 13
June.
F1 – F61
F1.
Munktell, Sara, Uppsala University
Bipolar Electrochemistry for High-throughput Corrosion Screening
F2.
Nagy, Geza & Livia, University of Pécs
Electrochemical study of the tetraferrocenyl-cavitand
F3.
Nazaruk, Ewa, University of Warsaw
Design and Assembly of pH-Sensitive Lipidic Cubic Phase Matrices for Drug Release
F4.
Neves, Marta, DropSens S.L
Electrochemical immunoassay based on a 96-well screen-printed ELISA plate for cardiac
troponin detection
F5.
Nouws, Hendrikus, ICETA
Multiplexed electrochemical immunosensor for detection of breast cancer markers
F6.
Nouws, Hendrikus, ICETA
Electrochemical immunosensor for Ara h 1 (a major peanut allergen) detection
F7.
Novakova, Katerina, University of Pardubice
Application of Silver Solid Amalgam Electrode for Determination of 5-Nitroindazole
F8.
Novotny, Ladislav, University of Pardubice
Behavior of Thiosulfate Anions on Charged Surfaces and Some Similarities with the
Agglomeration of Silver (Nano)Particles
F9.
Nöll, Gilbert, Siegen University
Construction of three-dimensional DNA hydrogels from linear building blocks
F10.
Nöll, Gilbert, Siegen University
Monitoring DNA hybridization by surface plasmon resonance (SPR), quartz crystal
microbalance (QCM) measurements, and electrochemical impedance spectroscopy (EIS)
F11.
Ojeda, Irene, Complutense University of Madrid
Electrochemical immunosensor for the determination of interleukin-6 using poly-HRP
streptavidin conjugates as labels for signal amplification
F12.
Okhokhonin, Andrei, Ural Federal University
Electrochemical detection of free cholesterol using potassium thiocyanate and nickel (II) and
cobalt (II) chlorides as electrocatalysts
F13.
Palomo-Marín, M.R., University of Extremadura
Electrochemical characterization of Bi sputtered screen printed electrode (BispSPE)
F14.
Pankratov, Dmitry, Malmö University
Hybrid electric power devices for simultaneous generation and storage of electric energy
F15.
Patris, Stéphanie, Université Libre de Bruxelles
Nano-immunoassay onto a screen printed electrode for HER2 breast cancer biomarker
determination
104
F16.
Pauliukaite, Rasa, Center for Physical Sciences and Technology
B-group vitamins as redox mediators in biosensing
F17.
Pedrero, María, Complutense University of Madrid
Novel electrochemical platforms for cardiovascular diseases diagnosis
F18.
Petrankova, Renata, University of Pardubice
Fitting Time-Dependence of Size of Silver Nanoparticles in Solutions Containing Silver Ions
F19.
Petrova, Ekaterina, Tomsk Polytechnic University
Electrochemical Determination of Coenzyme Q10 at a Glassy Carbon Electrode
F20.
Pifferi, Valentina, University of Milano
Electrodes modified by sulphonated Poly (Aryl Ether Sulphone) (S-PES) for electroanalytical
applications
F21.
Quan, Xueling, Technical University of Denmark
Characterization of Electromechanical Behavior of an Electrochemical Cantilever System
F22.
Rashid, Ashi, University of Leeds
Electrochemical study of Interaction of Prebiotic peptides with Hg Supported Phospholipid
Monolayers
F23.
Rueda, Fernando, University of Extremadura
Coupling of filtrating-bulk passive sampling and SWASV on screen printed gold electrodes
for on site determination of copper and lead in the soluble fraction of atmospheric deposition
F24.
Rumlova, Tereza, Charles University in Prague
Voltammetric Determination of 8-Nitroquinoline at Silver Solid Electrode in Model Samples
of Drinking and River Water
F25.
Rutyna, Iwona, Maria Curie Sklodowska University
Adsorptive stripping determination of folic acid using the in situ plated bismuth film electrode
F26.
Rutyna, Iwona, Maria Curie Sklodowska University
Molybdenum determination by adsorptive stripping voltammetry using solid lead electrode
F27.
Rutyna, Iwona, Maria Curie Sklodowska University
Application of a renewable silver based mercury film electrode to the determination of Ti(IV)
in water samples
F28.
Sadeghi, Susan, University of Birjand
Non-enzymatic electrochemical cholesterol sensor based on multiwall carbon
nanotubes/benzyl acetate modified screen-printed carbon electrode
F29.
Sadeghi, Susan, University of Birjand
A new amprometric benzaldhyde biosensor based on aldehyde oxidase immobilized on
Fe3O4-graphen oxide/ polyvinylpyrrolidone/polyaniline nanocomposite
F30.
Santos, Margarida, University of Lisbon
Direct Electrochemistry of nitrous oxide reductase from Marinobacter hydrocarbonoclasticus
at a carbon nanotube modified glassy carbon electrode
F31.
Sanver, Didem, University of Leeds
Interactions of Flavonoids with Lipid Monolayers
105
F32.
Schulz, Christopher, Lund University
An electronic tongue using cellobiose dehydrogenases from different origins to discriminate
various sugars and interfering analytes
F33.
Selesovska, Renáta, University of Pardubice
Electrochemical behavior and voltammetric determination of folates folic acid and leucovorin
and antifolate methotrexate using bare boron-doped diamond electrode
F34.
Sharma, Piyush Sindhu, Institute of Physical Chemistry PAS
Surface development molecularly imprinted polymer for isomer sensing
F35.
Sopha, Hanna, University of Pardubice
Macroporous Bismuth Film Electrodes Prepared on a Screen- Printed Substrate Electrode
for the Simultaneous Determination of Ni(II) and Co(II)
F36.
Sosa, Velia, University of Barcelona
Application of Bismuth film screen-printed electrode to study the metal complexation by thiolrich peptides
F37.
Soucková, Jitka, Palacký University
A voltammetric study of the interactions of pesticides with phospholipid structures
F38.
Stolarczyk, Krzysztof, University of Warsaw
Biocathode in self-powered system for dioxygen monitoring
F39.
Strzalkowska, Sylwia, University of Warsaw
Modified glassy carbon platform as a guanine sensor
F40.
Svecova, Hana, Palacký University
Influence of phospholipid layer on the selectivity of glassy carbon electrode for the
determination of paraquat
F41.
Szlezak, Monika, University of Warsaw
Cytochrome c biosensor based on liquid crystalline cubic phase doped with cytochrome c
reductase
F42.
Táborský, Jakub, Palacký University
Electrochemical oxidation of zopiclone
F43.
Tan, Shu Min, Nanyang Technological University
Towards electrochemical purification of chemically reduced graphene oxide: redox
accessibility of impurities
F44.
Tasca, Federico, USACH
Bilirubin oxidase from Myrothecium verrucaria physical adsorbed on graphite electrodes.
Insights into the alternative resting form of the enzyme and the impact of chloride,
temperature and pH
F45.
Tilli, Valeria, Technical University of Denmark
Impedance spectroscopic monitoring of the effect of phytochemical compounds on wound
healing in microfluidics
F46.
Tomaskova, Marketa, University of Pardubice
Determination of TBHQ in petroleum products using linear scan voltammetry with a gold
disc electrode
106
F47.
Trnkova, Libuse, Masaryk University
Biosensing of purine derivatives using a pencil graphite electrode modified by copper: a
promising tool in biomedicine
F48.
Ungureanu, Mihaela, University Politehnica of Bucharest
New 1-vinyl-azulenyl molecular ligands for the detection of lanthanide cations
F49.
Vacek, Jan, Palacký University
Electrochemical Analysis of Proteins Using Ionic Liquids as Solubilizers, Adsorption Solvents
and Electrolytes
F50.
Vagin, Mikhail, Linköping University
Boron-doped diamond microelectrode arrays for electrochemical monitoring of antibiotics
contamination in water
F51.
Vandeput, Marie, Université Libre de Bruxelles
Flow-through enzyme immobilized detector for the rapid screening of acetylcholinesterase
inhibitors
F52.
Vijalapuram Raghava Reddy, Kesava, Lund University
Photo-electrochemical communication between Rhodobacter capsulatus and electrode for
harnessing solar energy
F53.
Wikiel, Kazimierz, Technic, Inc
Detection and diagnosis of various contaminations in electroplating bath by a voltammetric
sensor: a case study
F54.
Wirzal, Mohd Dzul Hakim, Charles University in Prague
Voltammetric Behavior of Ampicillin and Penicillin G: Hanging Mercury Drop Electrode
(HMDE) VS Mercury Meniscus Modified Silver Amalgam Electrode (m-AgSAE)
F55.
Vyskocil, Vlastimil, Charles University in Prague
Large-surface carbon film electrode – A beneficial sensor for voltammetric determination
of electrochemically oxidizable organic compounds
F56.
Yáñez-Sedeño, Paloma, Complutense University of Madrid
Multiplexed determination of human growth hormone and prolactin at a label free
electrochemical immunosensor using dual carbon nanotubes-screen printed electrodes
modified with gold and PEDOT nanoparticle
F57.
Yuwadee, Boonyasit, Chulalongkorn University
Selective label free electrochemical impedance measurements of glycated haemoglobin on 3aminophenylboronic acid-modified eggshell membranes
F58.
Zachau-Christiansen, Birgit, Radiometer Medical
Blood Gas Analyzer with Solid State Sensors
F59.
Zavazalova, Jaroslava, Charles University in Prague
Boron Doped Diamond Electrodes: Influence of Boron Doping Level on Potential Window
and Determination of Oxidizable Organic Compounds
F60.
Zeng, Ting, University of Potsdam
Human sulfite oxidase on semiconductive nanoparticles with efficient bioelectrocatalysis
F61.
Zidaric, Tanja, National Institute of Chemistry
Multiple pulse galvanostatic preparation of bismuth particle electrode for trace toxic element
detection
107
F62.
Zima, Jiri, Charles University in Prague
Carbon Paste and Fibre Rod Electrodes in Determination of Biologically Active Organic
Compounds
F63.
Őri, Zsuzsanna, University of Pécs
Towards direct voltammetric determination of Ascorbic acid in natural pepper fruits without
sample treatment
108
T-1
Investigation of the chemical contents and the biological activities
Achillea fragrantissima (Forssk)
Nabila A. Al-Jaber, Asma A. Alenad
Chemistry Department, Faculty of Science, King Saud University, Riyadh, KSA.
[email protected]
Abstract:
The current study aimed for investigating the chemical contents and the biological activities of
one species of Compositae family which is Achillea fragrantissima (Forssk) grown in Saudi
Arabia. The two compounds were isolated from the alcohol extract of Achillea. Using
spectroscopic method including 1H-NMR, 13C-NMR, HMBC, HMQC, Mass and COSY,
those compounds were identified as 5, 3, 4-trihydroxy-3, 6, 7-trimethoxy flavonol (P1) and
5,3'-dihydroxy-3, 6, 7, 3-teramethoxy flavonol (P2) . The biological activity study revealed
that the extract from A. Fragrantissima, a herbal plant with known anti-inflammatory and
antiviral properties induced differentiation of CML cell line K652 leading to terminal
differentiation and apoptotic cell death. Several individual components of A. Fragrantissima
elicited similar differentiation effects like the crude extract and imply a general antioxidant
effect underlying differentiation and apoptosis. Due to its non-toxic nature, extract of A.
Fragrantissima may serve as potential CML therapeutic agent in patients resistant to tyrosine
kinase inhibitors. Tow compounds (P1, P2), obtained from A. fragrantissima ether extracts
were capable of inducing terminal differentiation of K562 cells which implied the presence of
multiple anticancer agents in the extract.
109
T-2
Tailoring the structure and the properties of pyrolysed carbon
electrodes
Letizia Amato, Lars Schulte, Arto Heiskanen, Anja Boisen, Stephan S. Keller, Sokol Ndoni,
Jenny Emnéus
Technical University of Denmark, Department of Micro- and Nanotechnology ([email protected])
Here we present a study with pyrolysed carbon derived from photoresist SU-8, polystyrene
(PS) and polystyrene-blockpolydimethylsiloxane (PS-PDMS) copolymers (Fig. 1) to evaluate
them as electrode material. XPS analysis showed that pyrolysed PS-PDMS contains an atomic
percentage of 29% silicon. The silicon content may be a limiting factor for obtaining highconductive structures due to lower carbon content (19%) compared to PS (96%) and SU-8
(98%), but at the same time the silicon is functioning as support for the 3D structure (fig. 1B).
Raman spectra of pyrolysed carbon derived from SU-8 photoresist, revealed the presence of
the so called D and G peaks (Fig. 1C), indicating that both amorphous and graphitic regions
are contributing. The peak intensity ratio of the D and G peaks varies with the microstructural
disorder of the carbon matrix1. From the Raman spectra, the calculated ID/IG is higher for
pyrolysed films of PS-PDMS (ID/IG = 1.1) compared to SU-8 and PS (ID/IG = 1), indicating
higher microstructural disorder of pyrolysed PS-PDMS. Additionally, the standard rate
constant for electron transfer (k0) was determined from the experimental ǻEp with the method
of Nicholson2 (table 1). The slower electron transfer kinetics of PS-PDMS compared to PS
and SU-8 films may be related to its lower carbon content, as well as to its higher
microstructural disorder .
Table 1. k0 values calculated from the
experimental ǻEp of the CVs obtained in 1mM
Ru(NH3)63+/2+, scan rate 10 mV s-1.
Figure 1. SEM images
of pyrolysed PS (A)
and PS-PDMS (B). C)
Raman spectra of
pyrolysed
films
derived
from
PSPDMS, PS, and SU-8.
respectively.
1.
2.
110
Electrode
material
PS-PDMS
ǻEp (mV)
109
k0 (cm s-1)
8,0E-02
PS
78
3,3E-01
SU-8
92
1,2E-01
Tuinstra, F. & Koenig, J. L. Raman spectrum of graphite. The Journal of Chemical Physics 53, 1126–1130 (1970).
Nicholson, S. R. Theory and application of cyclic voltammetry for measurement of electrode reaction kinetics. Analytical
chemistry 37, 1351–1355 (1965).
T-3
Large-scale quantification of CVD graphene surface coverage
Adriano Ambrosi, Alessandra Bonanni, Zdeněk Sofer and Martin Pumera*
Division of Chemistry & Biological Chemistry, School of Physical and Mathematical
Sciences, Nanyang Technological University, Singapore 637371, Singapore. ([email protected])
The extraordinary properties demonstrated for graphene and graphene-related materials can
be fully exploited when a large-scale fabrication procedure is made available. Chemical vapor
deposition (CVD) of graphene on Cu and Ni substrates is one of the most promising
procedures to synthesize large-area and good quality graphene films. Parallel to the
fabrication process, a large-scale quality monitoring technique is equally crucial. We
demonstrate here a rapid and simple methodology that is able to probe the eơectiveness of the
growth process over a large substrate area for both Ni and Cu substrates. This method is based
on inherent electrochemical signals generated by the underlying metal catalysts when
fractures or discontinuities of the graphene film are present. The method can be applied
immediately after the CVD growth process without the need for any graphene transfer step
and represents a powerful quality monitoring technique for the assessment of large-scale
fabrication of graphene by the CVD process.
Fig. 1 Schematic illustration of the
electrochemical determination of
CVD graphene surface coverage
on Ni (A) and Cu (B) surfaces. (a)
No signal is generated by a fully
covered metal; (b) signal generated
by the metal partially exposed from
the defective graphene film; (c)
uncovered metal generates the
maximum electrochemical signal.
111
T-4
Monoenzymatic amperometric biosensor for physostigmine detection
based on screen-printed electrode modified with
cobalt phthalocyanine-carbon black nanocomposite
R. Antiochia1, Fabiana Arduini2, Dana Neagu2, Giuseppe Palleschi2, Marilena Carbone2
1
Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, Piazz.le Aldo Moro 5, 00185
Rome, Italy
2
Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma Tor Vergata, 00133 Rome, Italy
Presenting author: [email protected]
Physostigmine salicylate is a carbamate drug acting as reversible acetylcholinesterase (AChE)
inhibitor [1]. The presence in the waste water of drug residues which act as AChE inhibitor is a
major problem due to their potential toxicity toward humans and animals and therefore a sensitive
and fast detection method is of great importance. Only few amperometric biosensors are reported in
literature for carbamate drug detection and most of them are bi-enzymatic, based on the coimmobilization of two enzymes, AChE and choline oxidase (ChO) [2]. One possible way to bypass
the use of two enzymes is the use of thiocoline, the non-natural substrate of AChE. The inhibition
degree of AchE can be monitored by the oxidation of enzymatically generated thiocoline (TCh). On
unmodified electrodes TCh is oxidised at very high potentials (+700 mV vs Ag/AgCl) and for these
reasons various mediators have been used in order to reduce the overpotential as well as problems
of surface passivation [3].
In this work, a novel monoenzymatic biosensor for physostigmine detection was developed based
on a screen-printed electrode (SPE) modified with a stable dispersion of cobalt phthalocyanine and
commercially available carbon black (CB). This probe showed significantly enhanced
electrochemical activity relative to a bare SPE towards TCh allowing amperometric detection of
TCh at very low applied potentials (+50 mV vs Ag/AgCl) with a linearity range from 0.03 to 0.08
mM and a detection limit of 0.01 mM.
The modified SPE was, then, used as substrate for the immobilization of AChE. We found a kMapp
for acethlthiocholine of 0.28 ± 0.05 mM, in good agreement with the KM (0.20-0.22 mM)
determined for the free enzyme in solution [4].
Analytical parameters such as mediator and enzyme concentration, substrate concentration and
incubation time for reversible inhibition of physostigmine were studied in order to optimize and
improve the elecrochemical performances of the biosensor.
Under optimum conditions, the physostigmine biosensor showed a very low detection limit (0.8
nM), good reproducibility and stability.
It is, therefore, suitable for future trace detection of physostigmine residue in wastewaters.
[1] I.B. Wilson, M.A. Harrison, S. Ginsburg, 1961, J. Biol. Chem., 1961, 236, 1498-1500.
[2] M. LeDoux, J, Chrom. A, 2011, 1218, 1021-1036.
[3] F. Arduini, A. Cassisi, A. Amine, F. Ricci, D. Moscone, G. Palleschi, J. Electroanal. Chem. 2009, 626, 66-74.
[4] F. Ricci, F. Arduini, C.S. Tuta, U.Sozzo, D. Moscone, A.Amine, G. Palleschi, Anal. Chim. Ata, 2006, 558, 164170.
112
T-5
The Use of Ethylenediamine Compounds for Differential Pulse
Anodic Stripping Voltammetric Determination of Copper(II) at a
Glassy Carbon Electrode
Syaza Azhari1, Rahmalan Ahamad1, Jiri Barek2 and Farediah Ahmad1
1
Department of Chemistry, Faculty of Science, UTM, 81310 UTM Skudai, Johor, Malaysia,
Charles University in Prague, Faculty of Science, University Centre of Excellence UNCE “Supramolecular
Chemistry”, Department of Analytical Chemistry, UNESCO Laboratory of Environmental Electrochemistry,
Albertov 6, CZ-12843 Prague 2, Czech Republic
E-mail: [email protected](Syaza Azhari) Tel:(60)-13-7047401
2
ABSTRACT:
The use of ethylendiamine Schiff bases (namely Bis(4-hydroxybenzaldehyde)ethylenediamine
(BBE), Bis(benzylidene)ethylenediamine (BZE) and N.N’-bis(2-hydroxy-4-metoxyacetophenone)ethylenediamine (BME) for a simple in-situ enhancement of Cu(II) detection using
differential pulse anodic stripping voltammetry (DPASV) was investigated. Redox potentials of
the ethylenediamines in 0.04 M Briton-Robinson buffer (BRB) pH 6.0 recorded using cyclic
voltammetry (CV) show sufficient difference from the expected redox potentials of Cu(II) ions.
The Cu(II) ions were accumulated on the surface of the electrode through formation of a
coordination complex with the ligands, which enhanced the sensitivity of the method. Optimum
performance was obtained by appropriate choice of supporting electrolyte and pH of the buffer,
amount of ligand used, the accumulation potential, accumulation time and scan rate. Under the
optimum conditions, the use of ethylenediamines allows 0.8, 5.5 and 14.1 fold increase for BBE,
BZE and BME, respectively, compared to the use of bare glassy carbon electrode. Detection
limits for Cu(II)- BBE, BZE, BME were, 0.012 μg/mL(2.0×10-7 mol/L), 0.0037μg/mL (5.8×10-8
mol/L) and 0.0023 μg/mL (4.0×10-8 mol/L), respectively. The practical applicability of this
technique was illustrated by the determination of Cu(II) ions at in tap water.
Keywords: Copper(II), Schiff Base, glassy carbon, stripping
Acknowledgement
Financial support from the Grant Agency of the Czech Republic (project P206/12/G151) is
gratefully acknowledged.
113
T-6
Versatile electrochemical sensor for tissue culturing and sample
handling
Tanya Bakmand, Dorota Kwasny*, Fatima Al-Zahraa Al Atraktchi*, Jaime Castillo-León and
Winnie E. Svendsen*
Technical University of Denmark (DTU), Department of Micro- and Nanotechnology (Nanotech), Nano Bio
Integrated Systems (NaBIS) group ([email protected])
* Technical University of Denmark (DTU), Department of Micro- and Nanotechnology (Nanotech), Nano Bio
Integrated Systems (NaBIS) group
Culturing of organtypic brain tissues is a routine procedure in neural research. The visual
inspection of the medium is the only way of determining the state of the tissue. At the end of
culturing, post-processing techniques such as HPLC can be used to measure the concentration
of the secreted metabolites in the waste products. Continuous measurements would enable
improved monitoring as compared to the end-point assay. Here, we developed a sensor
system capable of real time measurements of the analytes directly secreted from the tissue.
The presented system can be readily integrated in the standard procedures allowing for better
assessment of the progress of the culturing.
The sensor system was initially developed for monitoring of cells and tissue cultures but has
lately been considered for, and tested in, a wide range of applications. Some of these include
pathogen detection and integration in microfluidic devices for sample preparation.
In this work we present the development of the sensor system along with results on
characterization by impedance spectroscopy and cyclic voltammetry. Furthermore we present
recent results on integration of the sensor as well as amperometric detection of dopamine as a
preliminary proof of concept.
Figure 1. Left: Picture of a sensor prototype interfaced with PCB board. This setup has been used for
characterization and analyte detection. Right: CV measurements in 10 mM ferri-ferrocyanide using
sweep rates between 0.5 V/s and 0.05 V/s.
114
T-7
Voltammetric behaviour of ferrocene as probe molecule in
olive oils using a phosphonium-based ionic liquid as electrolyte
M. Antonietta Baldoa, Paolo Oliverib, Remo Simonettib, Salvatore Danielea
a
Department of Molecular Science and Nanosystems, Ca’ Foscari University of Venice, S. Marta 2137,
I-30123 Venice, Italy ([email protected])
b
Department of Pharmacy, University of Genoa, Via Brigata Salerno 13, 16147 Genoa, Italy
Voltammetric measurements in non-polar solvents have been traditionally impeded by the
lack of readily available, soluble and well-dissociated supporting electrolytes needed to
enhance their low conductivity [1]. In the past, the use of mixed non-polar and polar solvents,
containing conventional supporting electrolytes, has allowed undertaking some
electrochemical measurements of compounds soluble only in non-polar media [2]. More
recently, the extension of voltammetric methods into low-dielectric media has been made
possible by the use of room temperature ionic liquids (RTILs) [3]. These can be employed in
bulk as media to dissolve non polar compounds, or added in small amounts to the non polar
solvents, as electrolytes, to enhance their conductivity.
In this context, advantageous applications of RTILs have been recently reported for
enhancing the conductivity also of natural liquid matrices such as edible vegetable oils, which
are normally inaccessible to direct voltammetric measurements [4,5]. In particular, it has been
shown that the addition of tetraalkylphosphonium-based RTILs to maize and olive oil samples
has allowed to obtain meaningful cyclic voltammetric responses with a platinum microdisk
electrode, which has been exploited as an “electronic tongue” for differentiating oil samples
according to their quality and geographical origin [4], or for verifying the authenticity of
Italian PDO extra-virgin olive oils [5]. These goals have been achieved with a “blind
analysis” strategy based on the exploitation of the entire current-potential profiles in
conjunction with chemometric pattern recognition and class-modelling techniques.
The possibility of employing oil/RTIL mixtures to detect by voltammetry specific analytes in
edible oils is also of interest. In this case, knowledge of the mass transport properties of an
analyte in the media is an important step.
With this in mind, in the present study we report on the voltammetric behaviour of ferrocene,
taken as a probe molecule, in olive oil/RTIL mixtures. Because of its hydrophobic character,
ferrocene can mime in fact possible analytes (i.e. natural components or contaminants) which
could be present in edible oils. To this aim, the RTIL trihexyl(tetradecyl)phosphonium
bis(trifluoromethylsulfonyl)imide ([P14,6,6,6]+[NTf2]-), which has proven to solubilise over a
wide concentration range in the oil samples, has been here employed. Because of the high
viscosity of the media investigated, and to avoid problems related to ohmic drop,
measurements were taken with a Pt microdisk electrode.
1. N.W. Duffy, A.M. Bond, Electrochem. Comm. 8 (2006) 892-898
2. M. J. Pena, M. Fleishmann, N. Garrard, J. Electroanal. Chem. 220 (1987)31
3. L.E. Barrosse-Antle, A.M. Bond, R.G. Compton, A.M. Mahony, E.I. Rogers, D.S. Silvester,
Chem. Asian. J., 5 (2010) 202-230.
4. P. Oliveri, M. A. Baldo, S. Daniele, M. Forina, Anal. Bioanal. Chem. 395 (2009) 1135-1143.
5. P. Oliveri, M. Casale, M.C. Casolino, M.A. Baldo, F.Nizzi Grifi, M. Forina, Anal. Bioanal. Chem.
399 (2011) 2105 -2113.
115
T-8
Voltammetric method for rapid and sensitive determination of
herbicide triclopyr on bare boron-doped diamond electrode
Lenka Bandžuchová, Renáta Šelešovská and Jaromíra Chýlková
Institute of Environmental and Chemical Engineering, University of Pardubice, Studentská 573, Pardubice,
53210, Czech Republic ([email protected])
I (A)
Triclopyr (TCP, Fig. 1) is a selective systematic pyridine herbicide used to control woody and
herbaceous broadleaf plants along ways, in forests, and in grasslands. TCP acts as an auxin
mimic herbicide, which causes uncontrolled plant growth. TCP could stay in the environment
and its half-life in soils varied from 3.7 to 314 day [1]. Therefore a simple, sensitive and
reliable method for its determination is required. Voltammetry was for the first time used for
analysis of TCP and boron-doped diamond (BDD), a novel “green” electrode material, was
employed as a voltammetric sensor with very good results. Various voltammetric methods
were tested and differential pulse voltammetry (DPV) was evaluated as the most suitable. An
example of obtained linear dependence measured on BDD electrode using DPV is shown in
Fig. 1. Proposed method was applied for analysis of environmental and biological samples.
9E-06
6E-06
3E-06
0E+00
1
1.2
1.4
1.6
1.8
2
2.2
E (V)
Fig. 1 Structure and concentration dependence of TCP. The dependence was recorded on bare
BDD electrode using DPV in a range of concentrations from 5 to 108.8 μmol L-1 in a BrittonRobinson buffer solution of pH 2.
Acknowledgement
This work was supported by The Ministry of Education, Youth and Sports of the Czech
Republic (project No. CZ.1.07/2.3.00/30.0021).
Reference
[1] Tu, M., Hurd, C., & J.M. Randall, 2001. Weed Control Methods Handbook, The Nature
Conservancy, http://tncinvasives.ucdavis.edu, Version: April 2001.
116
T-9
Voltammetric determination of cymoxanil and famoxadone in river
water and soil
Bavol Dmytro, Jiri Zima, Jiri Barek, Hana Dejmkova
Charles University in Prague, Faculty of Science, Department of Analytical Chemistry, University Research Centre
Supramolecular Chemistry, UNESCO Laboratory of Environmental Electrochemistry, Albertov 6, CZ-128 43 Prague 2,
Czech Republic ([email protected])
Abstract
Differential pulse voltammetry (DPV) using a carbon fibre rod electrode (CFRE), a glassy
carbon electrode (GCE), and a capillary carbon paste electrode (CPE) have been used for the
determination of cymoxanil and famoxadone. Cymoxanil and famoxadone are industrially produced
as both curative and preventative foliar agricultural fungicides. In Europe, they are being sold on
crops including potatoes, tomatoes, hops, sugar beet and grapes to protect agricultural products
against various fungal diseases. Cymoxanil/famoxadone shows in aqueous environment methanol –
B-R buffer (1:9) single peak, whose position and height depends on pH. In the cathodic potential
range optimum conditions were found for the determination of cymoxanil by DPV at CFRE
(optimum pH 4, with relative standard deviation 1.36 % and with limits of quantification, LQ = 5.9
× 10–7 mol L–1) and at GCE (optimum pH 7, with relative standard deviation 0.68 % and with limits
of quantification, LQ = 5.6 × 10–7 mol L–1). In the anodic area for the determination of famoxadone
by DPV at GCE (optimum pH 4, with relative standard deviation 3.51 % and with limits of
quantification, LQ = 6.3 × 10–7 mol L–1) and at CPE (optimum pH 2, with relative standard deviation
8.27 % and with limits of quantification, LQ = 1.4 × 10–7 mol L–1).
Practical applicability of these newly developed methods was verified on model samples of
river water at CFRE and at CPE and soil at CFRE and at CPE.
The main advantages of this voltammetric method are its simplicity, cheap instrumentation
and easy manipulation with the electrodes. All types of the electrodes used in this work are easily
renewable, which eliminates most problems with working electrode passivation.
Acknowledgement
Financial support of the Grant Agency of the Czech Republic (project no. P206/12/G151) is
gratefully acknowledged.
117
T-10
An electrochemical gadolinium sensor based on
Gold surface functionalized with terpyridine ligands
Wahid Ben Mefteha, b,Yves Chevalier d, Hassen Touzic ,Rafik Kalfatb, Nicole JaffrezicRenaulta,*
([email protected])
a
Université de Lyon, Institut des Sciences Analytiques, UMR CNRS 5180, Université Claude Bernard Lyon 1,
43 bd 11 Novembre, 69622 Villeurbanne Cedex, France.
Laboratoire Méthodes et Techniques d'Analyse, Institut National de Recherche et d'Analyse Physico-chimique,
BiotechPole Sidi-Thabet, 2020 Sidi Thabet, Tunisia.
Đ
Laboratoire des Interfaces et Matériaux Avancés, Faculté des Sciences de Monastir, 5000 Monastir, Tunisia͘
d
Université de Lyon, Laboratoire d’Automatique et de Génie des Procédés, UMR CNRS 5007, Université
Claude Bernard Lyon 1, 43 bd 11 Novembre, 69622 Villeurbanne, France.
b
Abstract
The terpyridine molecule is an exceptional complexing ligand towards a broad range
of transition metal ions. The growing application of this molecule is the result of progresses in
the design and the synthesis of its derivatives. Consequently,terpyridine complexes can be
used in photochemistry for the design of luminescent devices or as sensitizers for light.
Terpyridines and their derivatives can form polymetallic species used in electrochemical
sensors,in medicinal chemistry and biochemistry.
The strong of chelation ability of these terpyridines towards lanthanide ions is
exploited in the present work for the design of chemical sensors. A method of
functionalization of the gold surface of sensor devices for the detection of lanthanide ions, in
particular Gadolinium(III) has been developed. The detection of Gd(III) is a major issue
because complexes of gadolinium are used in the medical field as contrast agents in IRM
although the Gd3+ ion is strongly toxic in its free form.The works includes the synthesis of the
starting materials based on terpyridine ligands and their grafting to gold surface by means of
different coupling agents for the sensitization of transducers based on gold. The modified
surfaces were characterized by various structural and morphological techniques such as
infrared spectroscopy in ATR mode, scanning electron microscopy and chemical analysis of
the surface by EDX. Electrochemical measurements gave a supplementary detailed
characterization of the materials and their ability to bind Gd(III) to their surface. The
application to the detection and analysis of lanthanide ions was studied by means of
impedimetric measurements that disclosed the favorable properties of the terpyridine grafted
layers:low detection limit and high sensitivity towards Gadolinium(III).
N
N
N
N
N
N
N
N
N
N
N
118
CH2
CH2
HN
HN
S
S
S
CH 2
CH 2
HN
HN
HN
O
S
N
N
CH 2
CH2
HN
N
N
N
N
N
O
O
S
S
Figure.Schematic representation for terpyridine self-assembly monolayers at the gold surface and Gadolinium(III) ions detected.
T-11
Miniaturized, reliable and fast potentiometric stripping analysis
of Hg(II) in environmental samples at screen-printed gold
electrodes
Elena Bernalte, Carmen Marín-Sánchez and Eduardo Pinilla-Gil
Departament of Analytical Chemistry, University of Extremadura
Av. Elvas s/n. 06006 Badajoz, Spain
([email protected])
We present in this work the development a simple, fast, sensitive, and cheap anodic
stripping potentiometric method (PSA) for Hg(II) monitoring. All experimental variables
involved in the PSA procedure (such as stirring speed, constant current, deposition time, and
deposition potential) were carefully optimized to develop a reliable method of measuring
dissolved Hg(II) in the low ng/mL range. The structural characterization of the gold inkprinted composition of the working electrode was also studied by using XPS, to elucidate the
nature of noticeable changes in the surface of the gold ink working electrode during the
optimization of the deposition potential parameter, already observed in previously published
works (1),
According to the IUPAC definition, the limit of detection obtained was 1.4 ng/mL for a
deposition time of 60 s, in line with the LOD of 0.5 ng/mL using 4 min deposition time
reported by Wang and Tian (2), and it is also comparable with the results previously described
using voltammetric methods for mercury determination at the same electrode (1).
The proposed method was evaluated using the NIST Standard Reference Material® 1641d
Mercury in Water. The applicability of the methodology was also successfully demonstrated
by analyzing Hg(II) in a non-pre-treated natural water sample. The potential applicability to
soil samples was tested by a simple strategy based on the combination of ultrasonic bath and
microwave extraction protocols with Hg(II) detection by the proposed potentiometric method.
The methodologies proved useful for the accurate analysis of Hg(II) in the NIST Standard
Reference Material® 2710a Montana Soil I, with a very good agreement.
The portability, sensitivity, and easy to use of miniaturized electroanalytical
instrumentation coupled with the simple and convenient ultrasonic bath and microwave
sample pre-treatments show the potential of this approach as a monitoring tool of
environmental Hg(II) in pollution assessment applications.
References:
(1) E. Bernalte, C. Marín-Sánchez, E. Pinilla-Gil. Analytica Chimica Acta 689 (2011) 60-68.
(2) J. Wang, B. Tian. Analytica Chimica Acta 274 (1993) 1-6.
Acknowledgements: This work is supported by the Spanish Ministry of Science and
Innovation (project CTQ2011-25388), European Union (FEDER) and Gobierno de
Extremadura (GR10091). E. Bernalte acknowledges a grant from Universidad de
Extremadura, Spain.
119
T-12
Electroanalytical behaviour of Gallic and Ellagic acid using
Graphene modified Screen-Printed Electrodes. Method for
the determination of total low oxidation potential phenolic
compounds content in cork boiling waters
Agustina Guiberteau-Cabanillas1, Belén Godoy-Cancho2, Elena BernalteMorgado1, Miriam Tena Villares1, Manuel A. Martínez-Cañas2
1
Department of Analytical Chemistry, University of Extremadura, Avda. Elvas, s/n. E-06071
Badajoz (Spain). E-mail: [email protected]
2
Institute of Cork, Wood and Charcoal, Centre for Scientific Research and Technology in
Extremadura (CICYTEX), P.I. El Prado, C/ Pamplona s/n. E-06800 Mérida (Badajoz-Spain).
All cork planks that are used for the production of stoppers undergo a treatment
by immersion in hot water at around boiling temperature for 1 hour, called cork boiling
water. These cork boiling waters show oxidation signals in Screen-Printed Carbon
Electrodes (SPCEs) modified with Graphene as a carbon based nanomaterial (see Fig.
1). Compounds such as Gallic acid (GA) and Ellagic acid (EA) occur naturally in cork,
and show oxidation signal in Graphene SPCEs (see Fig. 2).
2500
6000
2000
5000
I, nA
I, nA
Gallic Acid
Protocatechuic Acid
Syringic Acid
Vanillic Acid
4000
1500
1000
500
Coniferic Aldehyde
Ferulic Acid
3000
Sinapic Aldehyde
Syringic Aldehyde
2000
Vanillin
1000
0
-500
0.000
Ellagic Acid
0
0.200
0.400
0.600
E, V
Fig 1. DP voltammogram of 100μL of cork boiling
water in Graphene modified SPCE (final vol. 25 mL)
-1000
0.000
0.200
0.400
0.600
E, V
Fig 2. DP voltammograms of phenolic compounds from cork
in Graphene modified SPCE (1 ppm each one)
GA and EA have antioxidant, antimutagenic, antithrombotic, anti-inflammatory,
anti-viral and anticancer properties. These compounds show oxidation peaks closest to
the signals of cork boiling waters on Graphene SPCEs. For this reason, electroanalytical
behaviour of GA and EA was estudied on Graphene SPCE.
Experimental variables in the electroanalytical determination of GA and EA in
cork boiling water have been optimized. Reproducibility, repeatability and limit of
detection of the determination of these compounds on Graphene SPCE have been
analyzed. In order to evaluate the proposed method, real cork boiling water samples
have been measured using Folin-Ciocalteau reagent. A good correlation between both
methods has been found for the determination of total low oxidation potential phenolic
compounds content in cork boiling water. The proposed method is simpler and faster
than Folin Ciocalteau method.
Authors acknowledge FEDER, Gobierno de Extremadura (PCJ100501) and
GR10033 (FQM003-FEDER) for financial support.
120
T-13
Development of an amperometric glutamic acid biosensor for food
analysis
Beáta Bóka*, Helga Szalontai, Viktória Puizl
Food Science Institute, Eszterházy Károly College, Eszterházy tér 1, H-3300 Eger, Hungary
([email protected])
L-Glutamic acid (Glu) is a nonessential proteinogenic amino acid, which can be found in
foodstuffs both as the free and protein-bound forms. The free form of Glu, in its Lconfiguration, presents flavour enhancing properties. Its monosodium salt (monosodium
glutamate, MSG) is widely used as a flavour enhancer in the food industry. It gives the typical
aroma ‘‘umami”, recognized as the fifth basic taste. The excessive intake of MSG, may cause
allergic effects such as headache and stomach pain.
Glutamate is an important neurotransmitter in the mammalian central nervous system. The
glutamate level can be a useful marker for the diagnosis of several disorders, such as
schizophrenia, Alzheimer’s and Parkinson’s diseases, epilepsy or stroke. Therefore, the
glutamate determination is of great importance in food and clinical analysis [1].
Various analytical methods have been developed for glutamate determination based on
spectrophotometry, fluorescence, capillary electrophoresis and chromatography. However
these assays are time-consuming and inadequate for on site monitoring. Contrary to the above
mentioned methods, biosensors offer a simple, rapid and cost-effective solution. [2]
Our aim was to develop an enzyme-based amperometric biosensor for the fast determination
of glutamic acid content of food samples. Glutamate oxidase (EC 1.4.3.11) from Streptomyces
sp. was used with horseradish peroxidase (EC 1.11.1.7). The enzymes were immobilised on
the surface of a graphite electrode in a redox hydrogel with an Os mediator using
poly(ethylene glycol) (400) diglycidyl ether (PEGDGE) as crosslinker. The enzyme electrode
was used as a working electrode in a wall-jet type amperometric cell in three electrode
arrangement with a Ag/AgCl (0.1 M KCl) reference electrode and a platinum auxiliary
electrode. The biosensor worked in flow injection analysis system using a potentiostat
(QuadStat 164, eDAQ, USA) and an A/D converter (e-corder, eDAQ, USA). The effect of
hydrogel composition, pH and potential dependence were studied, the linear measuring range
was determined.
References
[1] T. Populin et al, Food Chemistry 104 (2007) 1712–1717.
[2] R. Monosík et al, Food Anal. Methods 6 (2013) 521–527.
121
T-14
Inherently Electroactive Graphene Oxide Nanoplatelets as Labels
for Single Nucleotide Polymorphism Detection
Alessandra Bonannia, Chun Kiang Chuaa, Guanjia Zhaoa, Zdeněk Soferb, Martin Pumeraa*
a
Division of Chemistry & Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang
Technological University, Singapore 637371 ([email protected])
b
Institute of Chemical Technology, Department of Inorganic Chemistry, 166 28 Prague 6, Czech Republic
Graphene materials are being widely used in electrochemistry due to their versatility and
excellent properties as platforms for biosensing. However, no records show the use of
inherent redox properties of graphene oxide as label for the detection. Here for the first time
we used graphene oxide nanoplatelets (GONPs) as electroactive labels for DNA analysis. The
working signal comes from the reduction of the oxygen containing groups present on the
surface of GONPs. The different ability of the graphene oxide nanoplatelets to conjugate to
DNA hybrids obtained with complementary, non-complementary and 1-mismatch sequences
allows the discrimination of single nucleotide polymorphism correlated to Alzheimer’s
disease. We believe that our findings are very important to open a new route in the use of
graphene oxide in electrochemistry.
Schematic of the experimental protocol. The hybridization step was performed with: complementary target (A);
1-mismatch target (B); non-complementary target (C).
122
T-15
An innovative EIS based 3D printed conductometer
Chiara Canali, Arto Heiskanen, Haseena Bashir Muhammad, Martin Dufva and Jenny
Emnéus*
[email protected]
*Department of Micro- and Nanotechnology, Technical University of Denmark, Kongens Lyngby, Denmark
Electrical conductivity (ı) is a measure of the ability of a material to carry a current. Testing
for ı is particularly significant when defining physico-chemical properties of electrolytes
since it is related to ionic strength, mobility and valence, and is sensitive to shift in
temperature, CO2 content, and therefore pH. For this reason, ı and its variation over time
convey a high degree of information, not only about inorganic and organic solutions, but more
importantly about dynamics of biological processes.
The simplest approach to determine ı is by applying an alternating electric field between two
electrodes and measuring the impedance value at the frequency for which phase angle value is
equal to 0Û. Modern instruments automatically adapt the frequency of analysis to the
particular measuring conditions1.
Here, an electrochemical impedance spectroscopy (EIS) based conductometer is presented as
a sensitive, low cost instrument able to correlate the whole impedance spectrum to the ı value
of solutions. The device can be easily 3D printed in acrylonitrile butadiene styrene (ABS) and
incorporates two rectangular gold plate electrodes (Fig. 1).
Figure 1: The EIS based conductometer interfaced with Reference 600 potentiostat (Gamry).
The cell constant of the measurement cell was determined to be 1.77±0.06 cm-1 by EIS
analysis on different ı standard solutions and then confirmed by geometrical measurements.
The device was tested by measuring ı of several dilutions of physiological phosphate
buffered saline (PBS) solutions in the range 10-4-10x exploiting both EIS and single
frequency analysis. Reproducible results were obtained and validated against a commercial
conductometer and literature search.
Taking together, all the results prove that the performance of the 3D printed conductometer
described here is comparable to that of the commercial instrument and serves as an
inexpensive and innovative alternative for quick evaluation of ı.
Reference:
1. “Conductivity. Theory and practice.” Radiometer Analytical
123
T-16
Electrochemical impedance spectroscopy is a versatile technique
for new challenges in 3D cell culture
Chiara Canali, Haseena Bashir Muhammad, Arto Heiskanen, Soumyaranjan Mohanty, Martin
Dufva, Anders Wolff and Jenny Emnéus*
[email protected]
*Department of Micro- and Nanotechnology, Technical University of Denmark, Kongens Lyngby, Denmark
Microtissue technology and 3D cell culture models have recently gathered attention by the
scientific community since they more effectively promote physiological functions of cell
differentiation and mimic tissue organization. In order to support cell adhesion and
proliferation, and stimulate the biological cross talk between cells and scaffold, the physicochemical properties and structural characteristics of the scaffold should be chosen carefully1.
Electrical impedance spectroscopy (EIS) has proven to be a powerful method to characterize
passive electrical properties of inorganic and organic materials2 but also of biological systems
both in vivo3 and in vitro4.
Different generations of EIS based sensors are here presented which were designed and
optimized in order to characterize new 3D polymeric scaffolds in terms of effective
conductivity, porosity and compactness.
The sensitivity field for EIS measurements on a volume conductor largely depends on the
electrode geometry (size, shape and orientation) and configuration (2-, 3- and 4-probe
measurements). Hence, different sensing configurations were designed, evaluated by finite
element simulations (Comsol Multiphysics) and experimentally characterized.
EIS characterization of scaffold materials and real-time monitoring of biological cell growth
under static and perfusion culture conditions were carried out.
a.
b.
c.
Figure 1: Three generations of sensors for 3D cell culture under static (a, b) and fluidic (c) conditions.
This method sets a next concrete perspective towards electrical impedance tomography
applications for on-line imaging of dynamic 3D cell culture environments.
References:
1. Methods in Molecular Biology 695:17-39 (2011)
2. Journal of advanced research in physics 1(1), 011006 (2010)
3. Physiological Measurements 30(2):129-40 (2009)
4. Nature 366, 591-592 (1993)
124
T-17
Parametric Signal Fitting by Gaussian Peak Adjustment
methodology for the analysis of the non-linear voltammetric data.
Santiago Cavanillas, José Manuel Diaz-Cruz, Cristina Ariño and Miquel Esteban.
Departament de Química Analítica, Facultat de Quíımica, Universitat de
Barcelona, Martí i Franquès 1-11, E-08028 Barcelona, Spain. ([email protected])
Voltammetry is commonly used in the study of speciation and complexation of metals. In
some systems of environmental and biological interest multivariate analysis is required to
evaluate the data. The use of multivariate curve resolution (MCR) methods especially
alternating least squares algorithm (MCR-ALS) has been widely applied [1] to different
systems but the method is restricted to voltammetric measurements with linear behaviour.
However this is not the usual situation in metal complexation studies by voltammetry. In most
cases, the complexes are not totally inert from an electrochemical point of view and this
causes a progressive shift of the signals along the potential axis and, hence, a loss of data
linearity. Also, changes in the electrochemical reversibility produce broadening or narrowing
of the signals thus causing a dramatic loss of linearity.
A new methodology, based on the parametric signal fitting (PSF) of peak-shaped
voltammetric signals has been developed to solve linear and non-linear voltammetric data.
The strategy consists on the fitting of two gaussian functions, one at each side of the signal,
and their parameters are least-squares optimised by means of an algorithm termed as gaussian
peak adjustment (GPA) [2]. The optimized parameters are directly related with the peak
height, position, area and symmetry, for the sake of a fast optimization and a straightforward
interpretation of the results. Focused in the complexation studies several transversal
constraints have been implemented to increase the consistency of the resolution along the
different signals of a voltammetric dataset [3]. The constraints deal with the evolution of peak
potentials versus pH and with the implementation of chemical equilibrium constants.
[1] M. Esteban, C. Ariño, J. M. Díaz-Cruz. Chemometrics in Electroanalytical Chemistry.
Critical Reviews in Analytical Chemistry 36 (2006) 295-313.
[2] S. Cavanillas, J. M. Díaz-Cruz, C. Ariño, M. Esteban. Parametric signal fitting by
gaussian peak adjustment: A new multivariate curve resolution method for non-bilinear
voltammetric measurements. Analytica Chimica Acta 689 (2011) 198–205.
[3] S. Cavanillas, N. Serrano, J. M. Díaz-Cruz, C. Ariño, M. Esteban. Parametric Signal
Fitting by Gaussian Peak Adjustment: implementation of 2D transversal constraints and its
application for the determination of pKa and complexation constants by differential pulse
voltammetry. Analyst 138 (2013) 2171–2180.
125
T-18
Real-time monitoring of drug-induced cytotoxicity kinetics using a
tailor-made impedance platform
Claudia Caviglia, Silvia Canepa, Kinga Zór, Arto Heinskanen, Thomas Lars Andresen and
Jenny Emnéus*
Department of Micro- and Nanotechnology, Technical University of Denmark ([email protected])
*Department of Micro- and Nanotechnology Technical University of Denmark
Monitoring of cellular activities, such as cell invasion, proliferation, differentiation and cell
death play a key role in understanding cellular behavior and opens up possibilities to unravel
new biological events critical in cancer research and drug screening [1]. Electrochemical
Impedance Spectroscopy (EIS) has been proved to be a powerful, label-free and minimally
invasive biophysical approach for continuous, real-time investigation of specific physiological
and morphological changes of adherent cells [2]. During the last two decades different
custom-made impedance-based systems have been designed and used for studying cellular
activities, such as cell adhesion and spreading [3], proliferation and cytotoxicity [4].
In this work, a tailor-made impedance-based platform [5] has been used to monitor in realtime the kinetics of drug-induced cytotoxicity using Doxorubicin (DOX) as a model
compound. A systematic study has been carried out in order to evaluate different parameters
that can alter the cell-substrate interaction and therefore be critical in cell-based impedance
measurements. In particular, in order to perform reliable biological assays, environmental
factors (evaporation, medium acidification, mechanical perturbations, and temperature
fluctuations), potential perturbations and cell density have been considered.
The time dependent kinetic response of DOX, a well-know chemotherapeutic drug, has been
evaluated on different densities of HeLa cells (12.500, 35.000 and 75.000 cells/cm2) (Figure
1) and a correlation between the time dependent kinetic action of the drug and the cell density
has been found (Figure 1 insert). The obtained results have been verified and compared with
data obtained from MTS assays performed under the same experimental conditions. MTS
assay does not provide a detailed overview of the kinetic of the biological events, proving the
great advantages of the impedance approach for studying specific biological problems.
References:
[1] M. M. Martinez, R. D. Reif, and D. Pappas, “Detection of
apoptosis: A review of conventional and novel techniques,” Anal.
Methods, vol. 2, no. 8, p. 996, 2010.
[2] I. Giaever and C. R. Keese, “Monitoring fibroblast behavior in
tissue culture with an applied electric field.,” Proc. Natl. Acad. Sci.
U. S. A., vol. 81, no. 12, pp. 3761–4, Jun. 1984
[3] J. Wegener, C. R. Keese, and I. Giaever, “Electric cell-substrate
impedance sensing (ECIS) as a noninvasive means to monitor the
kinetics of cell spreading to artificial surfaces.,” Exp. Cell Res., vol.
259, no. 1, pp. 158–66, Aug. 2000
[4] L. Ceriotti, J. Ponti, F. Broggi, a. Kob, S. Drechsler, E. Thedinga,
P. Colpo, E. Sabbioni, R. Ehret, and F. Rossi, “Real-time assessment
of cytotoxicity by impedance measurement on a 96-well plate,”
Sensors Actuators B Chem., vol. 123, no. 2, pp. 769–778, May 2007.
Figure 1. Impedimetric profiles relative to three different
populations of HeLa cells when treated with 5ȝM of DOX.
The insert represents the correlation between the cell density
and the time-dependent kinetic response.
126
[5] Caviglia, C, Carminati, M, Heiskanen, A, Vergani, M, Ferrari, G,
Sampietro, M, Andresen, TL & Emnéus, J 2012, 'Quantitative LabelFree Cell Proliferation Tracking with a Versatile Electrochemical
Impedance Detection Platform' Journal of Physics: Conference Series
(Online), vol 407, no. 1, pp. 012029
T-19
Electrochemical synthesis and characterisation of poly(folic acid)
films
Raimonda Celiešiūtė, Tautvydas Venckus, Šarūnas Vaitekonis, Aneta Radzevič and
Rasa Pauliukaite*
Department of Nanoengineering, Center for Physical Sciences and Technology, Savanoriu Ave. 231, LT-02300
Vilnius, Lithuania ([email protected])
*([email protected])
Folic acid (FA) is an electrochemically active molecule belonging to the B-complex vitamin
family. A number of FA detection methods has been intensively developed as it has a great
importance in biological functions of the organisms. The major functions of folic acid are:
DNA replication, its repair, methylation, etc. Nevertheless, the electrochemical behaviour of
the polymerised FA has been investigated insufficiently.
Poly(folic acid) (PFA) was synthesised by electrochemical polymerisation on various
electrodes in the pH range from 0 to 5 [1]. The PFA covered electrodes were additionally
modified with the graphene-chitosan-composite layer, which was investigated and optimised
previously [2], in order to stabilise the PFA film. The surface was characterised
microscopically, using atomic force microscopy, and electrochemically, employing
voltammetric techniques as well as electrochemical impedance spectroscopy. The
electrochemical properties and morphology of PFA will be presented and discussed.
References
1. R. Celiešiūtė, T. Venckus, Š. Vaitekonis, R. Pauliukaite, Electrochim. Acta, submitted.
2. R. Celiešiūtė, G. Grincienė, Š. Vaitekonis, T. Venckus, T. Rakickas, R. Pauliukaite, Chemija
24 (2013) 296.
Acknowledgement
This work is funded by the European Social Fund under the Global Grant measure, Project
No. VP1-3.1-ŠMM-07-K-01-124.
127
T-20
Influence of structure, interstitial cations, and structural defects
on electrocatalytic properties and stability of Prussian blue-based
catalysts for sensor applications
Sandra Čičić and Damir Iveković*
Department of Chemistry and Biochemistry, Faculty of Food Technology and Biotechnology, University of
Zagreb, Pierottijeva 6, HR-10000 Zagreb, Croatia ([email protected]; * [email protected])
Prussian blue (iron(III) hexacyanoferrate(II), PB) is one of the most commonly used
electrochemical catalysts in the field of chemical sensors in the last 25 years. Popularity of PB
is based primarily on the fact that in the reduced form it permits sensitive determination of
H2O2 at low cathodic potentials, at which the electrochemical interferences are minimal. This
property makes PB an ideal catalyst for the direct sensing of H2O2 or the use as a transducer
in first-generation amperometric biosensors based on oxidase enzymes. Crystal structure of
PB corresponds to a three-dimensional cubic covalent network consisting of alternating Fe2+
and Fe3+ ions bridged by cyanide ligands. Two forms of PB are usually distinguished: the
so-called "soluble PB" (KFe[Fe(CN)6]·nH2O) and "insoluble PB" (Fe4[Fe(CN)6]3·mH2O).
Due to the low solubility of PB and its rapid precipitation from aqueous solutions, PB formed
under ordinary conditions usually exhibits defect crystal structure and stoichiometry differing
from the ideal soluble and insoluble forms.
In this work the influence of structure, interstitial cations, and structural defects on
electrochemical properties of thin (25–100 nm) PB films was investigated. PB films were
electrochemically deposited on glassy carbon, Au, or ITO electrodes under galvanostatic or
potentiostatic conditions from solutions of different composition (Fe3+/ferricyanide ratio,
presence of complexing agents, pH). Insertion of cations other than preferential K+ into the
interstitial cavities of PB was performed by cyclical reduction and oxidation of PB in the
solution of target mono- and divalent cations. Composition of prepared PB films was
determined by laser-induced breakdown spectroscopy (LIBS). Electrochemical and
electrocatalytic properties of PB films were investigated by the combination of voltammetric,
spectroelectrochemical, and electrochemical quartz crystal microbalance measurements.
Performed investigations revealed that the electrocatalytic activity of PB towards H2O2
reduction can be significantly enhanced through the manipulation of PB structure at molecular
level (presence of structural defects / ferrocyanide vacancies, type of interstitial cation). It was
found that the structural defects in PB can act as highly active electrocatalytic sites capable of
reducing H2O2 at potentials higher than the N-coordinated Fe2+/Fe3+ redox couple of PB. It
was also found that the nature of interstitial cations strongly affects both the electrocatalytic
properties of PB and the stability of thin PB films in alkaline medium or in the presence of
millimolar concentrations of H2O2. Examples of PB-based electrocatalytic films at which the
reduction of H2O2 commences at potentials as high as 0.55–0.60 V (vs. Hg/Hg2Cl2/3.5 M
KCl), at which the diffusion limited sensing of H2O2 can be performed at potentials as high as
0.20 V, and which are fully stable in the presence of millimolar concentrations of H2O2 at pH
10 will be presented and their applicability in construction of amperometric biosensors based
on oxidase enzymes having optimal pH in the slightly alkaline medium will be demonstrated.
128
T-21
Electrochemical detection at screen-printed electrodes modified
with carbon nanotubes for the analysis of aminothiols in plant
samples
A. Dago, J. Navarro, C. Ariño, J.M. Díaz-Cruz, M. Esteban
Department of Analytical Chemistry, Faculty of Chemistry, University of Barcelona.
Martí i Franquès, 1-11, 08028 Barcelona (Spain), email: [email protected]
Phytoremediation technology is based on the use of plants to remove pollutants from the
environment or to reduce their toxicity to make them harmless. Plants have different strategies
to fight against heavy metal toxicity. Among them, the synthesis of thiol-rich compounds,
such as phytochelatins, is the main procedure. Phytochelatins (PCs) are small cysteine-rich
peptides with the general structure (γ-Glu-Cys)n-Gly (n=2-5), which are synthesised in plants,
algae and some fungi in response to heavy metal stress. Phytochelatins are involved in
detoxification and homeostasis of heavy metals by chelating these ions through the thiol
group in the cytosol and sequestering the metal-PC complexes in vacuoles.
The objective of this study is the application of HPLC with amperometric detection at screenprinted carbon electrodes (SPCE) to the analysis of PCs in plant samples and its comparison
with the traditional glassy carbon electrode (GCE). To improve the sensitivity of screenprinted electrodes, modifications of these electrodes with carbon nanotubes were considered,
as a preliminary test to assay the usability of these devices.
Taking into account that in plants treated with different toxic metals and metalloids the most
abundant thiols are GSH (γ-Glu-Cys-Gly) and PC2 ((γ-Glu-Cys)2-Gly) [1], these aminothiols
were considered for this study in addition to several isoforms of PC2 that had also been found
in plants [2]: PC2desGly ((γ-Glu-Cys)2), PC2Ala ((γ-Glu-Cys)2-Ala), PC2Glu ((γ-Glu-Cys)2Glu) and CysPC2 (Cys-(γ-Glu-Cys)2-Gly).
The separation was achieved using isocratic elution in a mobile phase of: 1% of acid formic
with 0.1 mol L-1 NaCl in ultrapure water at a pH of 2.00 (solvent A), and 1% of acid formic in
acetonitrile (solvent B). Mobile phase composition was 96:4 (solvent A:solvent B) at a flow
rate of 1.2 mL min-1. Amperometric measurements were done at a working potential of 1.0 V.
Good separation and detection were obtained for all the studied aminothiols (10-3 mol L-1)
with SPCE and GCE. As an example, chromatograms of a mixture of these thiols are showed.
GCE
SPCE
PC2desGly
CysPC2
GSH
GSH
PC2
PC2Glu
PC2Ala
PC2desGly
PC2
CysPC2
PC2Glu
PC2Ala
[1] A. Dago, I. González, C. Ariño, J.M. Díaz-Cruz, M. Esteban. Talanta 118 (2014) 201-209.
[2] A. Bräutigam, D. Schaumlöffel, G.-J. Krauss, D. Wesenberg. Anal. Bioanal. Chem 395 (2009) 1737-1747.
129
T-22
The use of Platinum Nanoelectrodes for the Detection of Hydrogen Peroxide
Alberto Citron, Daniele Veclani, Salvatore Daniele
Dipartimento di Scienze Molecolari e nano sistemi, University Cà Foscari Venice, Calle Larga S. Marta 2137, 30123
Venice, Italy.
[email protected]
Nanometer sized electrodes display intriguing features that can be successfully exploited for many purposes and, for
electroanalysis, in confined environments over nano- and pico-liter levels. For instance, nanoscale devices have been
used for probing chemicals in individual cells. The potential benefits of nanoelectrodes compared to electrodes of larger
dimensions have been demonstrated by numerous workers. Such benefits include enhanced mass transport, increased
signal-to-noise ratio, greater sensitivity and increased immunity to hydrodynamic perturbations. However, there still
remain considerable challenges in the production of robust, reproducible nano-scale devices and the extent to which
these theoretical benefits can be realized experimentally. This arises, at least in part, from the complexities involved in
nanoelectrode fabrication and the verification of electrochemical performance post fabrication. Reproducible
nanoelectrode fabrication with highly controlled electrode geometry can be achieved by pulling metal micro-wires into
glass capillaries with the help of a laser pipette puller. In particular, gold, silver and platinum nanodisk electrodes have
been fabricated with such procedure.
Platinum materials are widely used electrocatalysts for oxidation and reduction of H2O2. However, the current response
to hydrogen peroxide is under mixed kinetic and diffusion control and further complicated by competitive adsorption of
oxygen onto Pt active surface sites and the protonation of the adsorbed H2O2 complex species. Therefore, a lack of Pt
surface sites limits the rate of the electrode process and causes a current depression for higher H2O2 concentrations.
High surface platinum black and mesoporous platinum microelectrodes have been used for H2O2 detection, because
they circumvent the problems related to the limited number of active sites.
In this paper we report on the voltammetric behaviour of hydrogen peroxide in phosphate buffer media at disk
nanoelectrodes, and show that the current responses at these electrodes are larger than those predictable on the basis of
the geometric surface area and mass transport coefficient. This is due to the fact that these kinds of platinum
nanoelectrodes display an effective surface area much larger than their geometric surface area.
1200
800
1,4
1 mM
3 mM
5 mM
10 mM
20 mM
Anodica
Catodica
1,2
1,0
400
0,8
i(pA)
i (nA)
0
0,6
-400
0,4
0,2
-800
0,0
-0,2
0,0
0,2
E(V) vs Ag/AgCl
0,4
0,6
0
5
10
15
20
25
30
[H2O2] (mM)
Figure - Steady-state voltammetry recorded at a platinum nanoelectrode 38 nm radius in a phosphate buffer solution containing H2O2 at
different concentrations and calibration plots.
130
T-23
Study of the complexation of Pb(II) with meso-2,3dimercaptosuccinic acid and 2,3-dimercapto-1-propanesulphonic
acid using a bismuth-bulk rotating disk electrode
M. de la Gala Morales, C. Ariño*, J.M. Díaz-Cruz*, M. Esteban*, M.R. Palomo Marín, L.
Calvo Blázquez, E. Pinilla Gil
Department of Analytical Chemistry, University of Extremadura, Av. de Elvas s/n, 06006 Badajoz, Spain
([email protected])
*Departament de Química Analítica, Universitat de Barcelona, Martí i Franquès, 1-11, E-08028 Barcelona,
Spain
A lot of products which we use daily (paint, pipes, plumbing materials, batteries, cosmetics,
etc.) are still made of lead despite its harmful effects on health. Children are more sensitive to
the damaging of lead and can also be more highly exposed to this metal due to the fact that
they can touch them or put these lead objects in their mouth. The treatment of lead poisoning
is the chelation, in which compounds such as meso-2,3-dimercaptosuccinic acid (DMSA) and
2,3-dimercapto-1-propanesulphonic acid (DMPS) are used as therapeutic agents. These metal
chelators exhibit a higher solubility in water, lower toxicity and are more effective than other
chelating agents such as, for example, dimercatopropanol (BAL)[1]. Complexation studies of
different systems have been carried out by electrochemical techniques employing mainly
mercury electrodes [2,3]. Due to the toxicity of mercury, new materials are tested for
replacing this metal in the construction of the electrodes. Among them, bismuth-based
electrodes have been demonstrated as a good alternative and its applicability for following of
complexation of heavy metals has been reported [4,5]. In the present work, for the first time,
bismuth bulk rotating disk electrode (BiB-RDE) was used successfully for the study of the
complexation of Pb(II)-DMSA and Pb(II)-DMPS by differential pulse voltammetry (DPV).
Multivariate curve resolution by alternating least squares (MCR-ALS) was applied to the
voltammetric data for obtaining the stoichiometries of the complexes formed. Reversibility of
each system analyzed was evaluated by cyclic voltammetry (CV). The suitability of the BiBRDE to carry out studies of metal complexation and the advantages that it presents over
mercury and bismuth film electrodes, encourage us to futher investigating new applications of
this electrode in the health and environmental fields.
References
[1] Domingo J.L., Reproductive Toxicology 1995, 9, 105.
[2] Alberich A., Díaz-Cruz J.M., Ariño C., Esteban M., Analyst, 2008, 133, 470.
[3] Cavanillas S., Chekmeneva E., Ariño C., Díaz-Cruz J.M., Esteban M., Anal.Chim.Acta,
2012, 746, 47.
[4] Alberich A., Serrano N., Díaz-Cruz J.M., Ariño C., Esteban M., Talanta, 2009, 78, 1017.
[5] Sosa V., Serrano N., Ariño C., Díaz-Cruz J.M., Esteban M., Talanta, 2013, 107, 356.
131
T-24
Monitoring the photodegradation of pollutant phenolic
compounds by means of an electronic tongue
Xavier Cetó, Andreu González and Manel del Valle*
Sensors and Biosensors Group, Department of Chemistry, Universitat Autònoma de Barcelona,
Edifici Cn, 08193 – Bellaterra (Spain) ([email protected])
Phenolic compounds are widely used in industry as antioxidants, chemical intermediates,
additives to lubricants and gasoline, disinfectants, tanning agents, photographic developers or
in the production of drugs and pesticides, between others [1]. However, despite its extensive
usage, some of them are known to possess well-known adverse health effects and are
consequentially regulated as priority pollutants, by both the US Environmental Protection
Agency (EPA) and the European Union (EU) [2]. Therefore, removal and control of these
compounds from industrial waste, where they act as recalcitrant pollutants, is a critical issue.
Current official analytical methods for phenolic compounds detection imply separation steps
(liquid-liquid extraction or solid phase extraction for liquid samples, and Soxhlet extraction
for solid samples) followed by chromatography using different detection devices, where they
may require also a derivatization step) [2]. Unfortunately, these methods may require
expensive and hazardous organic solvents, which are undesirable for health and disposal
reasons; in addition, the analysis is labour intensive and takes long time. Hence, there is a
general trend to find alternatives that may also be utilizable for on site analyses.
In this direction, biosensors provide an interesting approach to the determination of phenolic
compounds due to their low cost, fast response and because they can be easily used to carry
out on-field analyses. In their more recent trends, the coupling with the usage of chemometric
tools such as artificial neural networks (ANNs) might help to avoid and/or counterbalance
any interference problem, an approach known as (bio)electronic tongue. Thus, with this
methodology, it is possible to achieve a parallel determination of a number of different
species, while any interference effect is solved using these advanced chemometric tools [3].
The aim of this work is to prove the applicability of a voltammetric biosensor device
employing electronic tongue principles to the monitoring of different phenolic pollutants in
waste waters. The proposed approach is based on the coupling of cyclic voltammetric
responses obtained from a phenol enzyme biosensor with chemometric tools such as ANNs.
The biosensor used was a bienzymatic biosensor containing two phenolic related enzymes,
tyrosinase and laccase, with the aim of obtaining a wider scope of response to target phenolic
compounds. ANNs were used for building the quantitative prediction models. To this end, the
response model was first built employing a set of standards prepared based on a factorial
design; afterwards, and once validated, it was applied to the monitoring of the titanium oxide
(TiO2) photocatalytic oxidation of three phenol pollutants under UV light.
[1] K. Farhod Chasib, J. Chem. Eng. Data 2013, 58, 1549.
[2] D. Puig, D. Barceló, TrAC-Trend. Anal. Chem. 1996, 15, 362.
[3] M. del Valle, Electroanalysis 2010, 22, 1539.
132
T-25
Design and Fabrication of Printed Electrochemical
Immunosensors for Progesterone Testing – AURO-QUANT
Aoife Delaney1, Jeseelan Pillay2, Robert Tshikhudo2, Baljit Singh1, Brian Seddon1, Eithne
Dempsey1
1
Centre for Research in Electroanalytical Technologies (CREATE) Institute of Technology Tallaght, Dublin 24
2
Mintek, Nanotechnology Innovation Centre, Johannesburg, South Africa, 2125
Abstract
Profitability in the dairy industry is heavily dependent on the accuracy of progesterone
measurement, with periodic assessment of hormone levels in herds being utilised to
determine the most fertile ovulation time for artificial insemination. Point of care and inline instruments, coupling ELISA techniques with electrochemical detection have been
explored in order to quantify progesterone in bovine milk and serum, yet practical
implementation of a sensitive, rapid, low cost test remains a technical challenge. The
end goal of this study envisages development of a thin-layer mesofluidic system
integrating rapid flow immunochromatography to electrochemical detection for the onsite monitoring of progesterone in cow’s milk. The Immuno-Cap device may be
described as a micro-capillary biosensor and is based on redox activity of nanogold as
the signalling element of the competitive ELISA format. Figure 1 shows a schematic of
the antibody coated micro-channel, and a redox responsive electrode-sensor (Au
stripping wave Figure 2). Synthetic research approaches will investigate compounds
capable of both co-ordinating to gold nanoparticles through thione functionality while
also providing amine functionality to facilitate the Schiff base link to the target
molecule, progesterone. The assay principle is based on a competitive format between
free progesterone in the sample and progesterone labelled with gold nanoparticles
(immunoconjugate) for binding sites on the internal wall of the capillary, which has been
coated with anti-progesterone antibody. The quantity of conjugate arriving at the
electrode is detected electrochemically and is related to free progesterone concentration
in the sample.
Figure 1. Schematic representation of Immuno-Cap illustrating the structure of a single-channel device
and the competitive immunoassay protocol for
progesterone.
Figure 2. Cyclic voltammogram profiles for
increasing Au nanoparticle concentration following
anodic deposition and subsequent cathodic stripping –
confirming signal generation for surface confined Au.
133
T-26
SYNTHESIS AND FUNCTIONALIZATION OF Fe 3O4@Au
CORE-SHELL NANOPARTICLES FOR THE
ELECTROCHEMICAL DETECTION OF MAIZE MON810
M. Freitas1,3 , M. F. Barroso1 , C. Pereira2 , C. Freire2 , N. de-los-Santos-Álvarez3 , A.J. MirandaOrdires3 , M.J. Lobo-Castañón3 , C. Delerue-Matos1*
1
REQUIMTE, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Portugal
2
3
REQUIMTE, Faculdade de Ciências, Universidade do Porto, Portugal
Departamento de Química Física y Analítica, Universidad Oviedo, Spain
([email protected]) *[email protected]
Analytical methods are required for reliable and accurate detection and quantification of
genetically modified organisms (GMO), not only to verify the compliance with legislation,
but also to help manufacturers improving their food/feed production in terms of hazard
analysis of critical control points (HACCP), risk assessment and good manufacturing
practices.
The application of electrochemical genoassays in the field of food analysis represents a
promising method to explore because of the easy, inexpensive and rapid detection of GMO. In
this work, a sensitive genoassay using iron oxide/gold core/shell (Fe 3 O4 @Au) magnetic
nanoparticles for the detection of a specific sequence of MON810 maize event was
developed. Monodispersive magnetic iron nanoparticles were synthesized according to [1], by
a thermal decomposition method. In a second step, the magnetic iron cores were coated with a
gold shell, following a modified procedure based on [2]. Figure 1 shows a TEM image of the
Fe3 O 4 @Au nanoparticles which reveals that the average particle diameter was 15 ± 3 nm.
Figure 1: TEM image of the Fe3 O 4 @Au
To construct this genoassay, a binary self-assembled monolayer composed by
mercaptohexanol (MCH) and thioctic acid (TOA) was optimized and a sandwich format assay
by using enzymatic labels and chronoamperometry detection was performed.
[1] Sun, S., Zeng, H., Robinson, D.B., Raoux, S., Rice, P.M., Wang, S.X., Li, G. J. Am.
Chem. Soc., 126 (2004) 273–279
[2] Wang, L., Luo, J., Fan, Q., Suzuki, M., Suzuki, I.S., Engelard, M.H., Lin, Y., Wang, J.Q.,
Zhong, C.J. (2005) J. Phys. Chem. B, 109 (2005) 21593–21601.
Acknowledgements: This work was supported by Spanish Government (Project PRI-AIBPT-2011-0769), Ações
Luso-Espanholas (Project Nº. 38/12) and by the FP7-Marie Curie International Research Staff Exchange Scheme
(IRSES) project GMOsensor. N.S.A. thanks to Spanish Government for a Ramón y Cajal contract. M.F.B is
grateful for the pos-doc fellowship (SFRH/BPD/78845/2011) financed by POPH-QREN-Tipologia 4.1Formação Avançada, by Social European Fund and Ministério da Ciência, Tecnologia e Ensino Superior.
134
T-27
ULTRASENSITIVE ELECTROCHEMICAL APTASSAY FOR
DETECTION OF GLUTEN IN FOOD: IMPROVING CELIAC
PATIENTS’ SAFETY
S. Amaya-González, N. de-los-Santos-Álvarez, A. J. Miranda-Ordieres, M. J. LoboCastañón*
Departamento de Química-Física y Analítica. Universidad de Oviedo
Av. Julián Clavería, 8, 33006 Oviedo (Spain)
([email protected]), *[email protected]
Celiac disease (CD) is an autoimmune disorder characterized by an inflammation of the small
intestine induced for the ingestion of storage proteins from wheat, barley, rye, and probably
oat known as gluten. The only known treatment by now is the strict lifelong diet without
gluten. However, the ubiquitous presence of gluten in the western human diet poses patients
at high risk. EU legislation in force establishes 20 ppm as threshold for labeling a product as
“gluten-free”. Unfortunately, even trace amounts of gluten can trigger an adverse response in
sensitized individuals but decreasing the threshold is currently not feasible because of the lack
of reliable analytical methodology with suitable detectability.
To fill this gap, we propose the use of aptamers as alternative molecular receptors to
antibodies employed in official and commercial methods. Using SELEX, several aptamers
against the most immunotoxic fragment of the -gliadin, the gluten protein from wheat, were
selected. The aptamer with the highest affinity to 33-mer peptide was used in a competitive
electrochemical enzyme linked aptassay on magnetic microparticles modified with the target.
This method allows us to reduce the limit of detection from 3 ppm (official method based on
R5 antibody) to 0.5 ppm of gluten (0.5 ppb of gliadin standard). Besides, unlike R5, the
aptamer recognize all toxic proteins for celiac patients including oats with no cross-reactivity
with rice, maize, or soya. The implementation of this approach might diminish the current
threshold protecting CD patients more effectively. Our approach is under international patent
application.
Wash
+
Measurement
Substrate
TMB + H2O2
+
33-mer peptide
3
Biotinylated
Aptamer
Biot
Competition
Wash
Streptavidin-HRP
St
PWG Gliadin
Acknowledgments: S.A.G. and N.S.A. thank to Spanish Government for a predoctoral grant FPI and a Ramón y
Cajal contract, respectively. This work has been financed by Project CTQ2008-02429 and FEDER Funds.
135
T-28
Pencil-drawn electrodes for paper-based electrochemical devices
N. Dossi, R. Toniolo, G. Bontempelli, F. Terzi*, E. Piccin**
Department of Food Science, University of Udine, Udine, Italy ([email protected])
*Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Modena, Italy
**Department of Chemistry, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
The use of portable writing tools suitable for drawing conductive lines on paper appears to be
particularly attractive for assembling inexpensive devices in developing countries and
resource-limited remote regions where advanced technologies and infrastructures are not
available [1]. Recently, a simple approach based on the use of commercial pencil leads has
been succesfully employed for assembling even quite complex electrochemical circuits for
paper-based microdevices [2, 3]. An additional advantage offered by pencil leads consists in
the fact that they can be suitably doped with convenient modifiers during their preparation.
A simple procedure for assembling homogeneously doped pencil leads suitable for drawing
electrodes with desired properties on paper based electrochemical devices is presented.
It involves mixing of controlled amounts of the desired mediator with carbon powder
(conductive material), sodium bentonite (binding agent) and sodium silicate (hardening
agent). The resulting mixture is then forced within a thin metal tube to build up rods which
can be mounted on lead holders. Commercial metal-based or graphite modified by metal
electrodeposition can be alternatively used to assemble pencil leads suitable for drawing
working or reference Ag/AgCl electrodes on paper supports.
Such modified pencil leads make possible the quick and easy preparation of inexpensive
electrochemical cells able to provide reliable and fairly reproducible results for several oneuse applications. They appear also particularly promising for assembling inexpensive
electrochemical detectors for the quantitative determination of analytes separated by on-plate
schemes, such as thin-layer chromatography or electrophoresis on solid porous supports.
lead holder
graphite mixture
pencil lead
graphite rod / pencil lead
graphite marks
paper-based EC device
[1] Russo A, Ahn BY, Adams JJ, Duoss EB, Bernhard JT, Lewis JA, Adv. Mater. 23 (2011)
3426.
[2] Dossi N, Toniolo R, Pizzariello A, Impellizzieri F, Piccin E, Bontempelli G,
Electrophoresis 34 (2013) 2085.
[3] Dossi N, Toniolo R, Piccin E, Susmel S, Pizzariello A, Bontempelli G, Electroanalysis, 25
(2013) 2515.
Financial support from the Italian Ministry for University and Research (MIUR) through
project FIRB “Futuro in Ricerca” RBFR13NZH9 is gratefully aknowledged.
136
T-29
Biobattery powered sensor for neurotransmitters
Sylwia Dramińska, Dominika Majdecka, Renata Bilewicz, Paweł Krysiński, Jerzy
Golimowski
Faculty of Chemistry, University of Warsaw Pasteura 1, Warszawa 02-093, Poland
e-mail address: [email protected]
The advantages of biobatteries include easy miniaturization and utility for powering small
devices e.g. sensors, switches, watches and other electronic devices. Recently, we have shown
the biobattery parameters and its application for powering a clock [1]. Our aim was to
optimize the construction of the biobattery and couple it with a biosensor for neurotransmitter
detection. Arylated multiwall carbon nanotubes with bound laccase are used on the cathode
for the reduction of oxygen and zinc disc covered with hopeite is the anode. Arylated carbon
nanotubes increase the working surface of the electrode, and provide direct contact with the
active sites of laccase. The electrode substrate is carbon paper. The zinc – air sandwich
biobattery works under stationary or flow conditions. The system including sandwich
biobattery connected with a mini potentiostat and the microelectrode sensor was employed for
monitoring selected neurotransmitters.
1. Stolarczyk; M. Kizling; D. Majdecka; K. Zelechowska; J. F Biernat; J. Rogalski; R.
Bilewicz „Biobatteries and Biofuel Cells with Biphenylated Carbon Nanotubes” J. Power
Sources, 2014, 249, 263–269
137
T-30
Linking glucose oxidation to electrochemiluminescence using
bipolar electrochemistry
Vera Eßmanna, Daliborka Jambreca, Alexander Kuhnb, Christian Amatorec,
Wolfgang Schuhmanna
a
Analytische Chemie – Elektroanalytik & Sensorik, Ruhr-Universität Bochum, Universitätsstraße 150, 44780
Bochum, Germany (email: [email protected])
b
Université Bordeaux, ISM, ENSCBP, 33607 Pessac, France
c
École Normale Supérieure, Département de Chimie, UMR CNRS-ENS-UPMC 8640 “Pasteur”, 24 rue
Lhomond, 75231 Paris Cedex 05, France
Bipolar electrochemistry can be used to determine the concentration, type or property of
analytes in a wireless manner, when the electrochemical detection of the analyte is coupled to
an optical reporting reaction.
Here, we show that the presence of glucose in solution can be visualized by triggering electrochemiluminescence via bipolar electrochemistry. At the cathodic pole of the bipolar electrode
glucose was oxidized by means of glucose oxidase, immobilized within an anodic electrodeposition polymer, on top of an electrochemically deposited Prussian Blue (PB) film (see
Figure). The necessary potential for the subsequent reduction of enzymatically generated hydrogen peroxide at the cathodic pole catalyzed by PB was generated using the feeder electrodes in the bipolar setup. The electrons are provided by the concomitantly occurring electrochemiluminescence at the anodic pole invoked by the oxidation of luminol in the presence of
hydrogen peroxide. The luminescence was recorded using a photomultiplier tube located
underneath the anodic pole compartment. Anodic luminol electrochemiluminescence hence
allows monitoring the presence of glucose in the cathodic pole compartment.
Figure - At the cathodic pole glucose is enzymatically oxidized; the produced hydrogen peroxide is
electrocatalytically reduced at the underlying PB film. Proportional electrochemiluminescence is
triggered at the anodic pole in the presence of glucose in the cathodic pole compartment.
The proposed bipolar electrochemistry system can be extended for the detection of a variety
of other potential analyte molecules by exchanging the immobilized enzyme. Future work
will be directed towards the simultaneous detection of several analytes in a specifically designed electrode microstructure.
138
T-31
Multiplexed determination of amino terminal pro-B-type
natriuretic peptide and C-reactive protein cardiac biomarkers in
human serum at a disposable electrochemical
magnetoimmunosensor
B. Esteban-Fernández de Ávila,a V. Escamilla-Gómez,a V. Lanzone,b S. Campuzano,a M.
Pedrero,a D. Compagnoneb and J. M. Pingarrón.a
a
b
Departamento de Química Analítica, Facultad de CC. Químicas, Universidad Complutense de Madrid,
E-28040 Madrid, Spain. ([email protected]).
Department of Biosciences and Technology for Food Agriculture and Environment, University of Teramo, via
Carlo R. Lerici 1, 64023 Mosciano S. Angelo (Teramo), Italy
Several protein biomarkers have been associated with increased relative risk for
cardiovascular diseases (the major cause of death among adults worldwide), and their
simultaneous detection have demonstrated to provide a more accurate diagnostic tool and
enhance significantly the predictive value for the risk factor [1].
In this work, the first disposable amperometric magnetoimmunosensor for the simultaneous
determination of amino-terminal pro-B-type natriuretic peptide (NT-proBNP) and C-reactive
protein (CRP), by using indirect competitive and sandwich configurations, respectively, and
horseradish peroxidase-labeled tracers, is reported (Figure 1). The use of carboxylic acidmodified magnetic beads (HOOC-MBs) allowed the covalent immobilization of specific
antibodies and antigens, and dual screen-printed carbon electrodes (SPdCEs) allowed
achievement of simultaneous independent amperometric signals. The developed methodology
showed excellent analytical performance in terms of sensitivity (LOD of 0.47 ng mL-1 for
both biomarkers), selectivity and a wide range of quantifiable concentrations. An international
standard for CRP serum spiked with NT-proBNP was analyzed successfully, demonstrating
the usefulness of the dual magnetoimmunosensor as an alternative diagnosis tool for the
development of POC devices for onsite clinical diagnosis.
Figure 1.- Schematic display of the fundamentals involved in the development of the disposable dual
magnetoimmunosensor for the simultaneous determination of NT-proBNP and CRP.
[1] B. Esteban-Fernández de Ávila, V. Escamilla-Gómez, V. Lanzone, S. Campuzano, M. Pedrero,
Compagnone, J. M. Pingarrón, Electroanalysis. 2014, DOI: 10.1002/elan.201300479.
D.
139
T-32
Polypyrrole-Au Nanoparticles Composite as Suitable Platform
for DNA Biosensor with EIS Detection
Michal Fau, Tomasz Rapecki, Mikolaj Donten, Anna M. Nowicka*
Faculty of Chemistry, University of Warsaw, Pasteura 1, PL 02-093 Warsaw, Poland; [email protected]
*Faculty of Chemistry, University of Warsaw, Pasteura 1, PL 02-093 Warsaw, Poland;
[email protected]
Application of a composite consisting of PPy and Au Nps to the construction of
sensing layer in DNA biosensors led to the increase in the number of probe DNA strands in
the layer by at least two orders of magnitude compared to the thiol intermediate layers. The
probe DNA strands attached to the Au nanoparticles in the composite layer were fully
available for the hybridization process. The examination of the composites containing a
constant amount of Au nanoparticles and varying in PPy-layer thickness was done using
electrochemical impedance spectroscopy, voltammetry and scanning electron microscopy.
The optimal PPy layer thickness was determined to be in the range 10÷20 nm. Such thickness
of the polymer layer led to the elimination of aggregation of metal nanoparticles
electrodeposited at the PPy surface. The sensor response (ΔRct) increased linearly with
logarithm of concentration of target DNA in the range 2 10-13÷2 10-6 M. The obtained
detection limit of target DNA in the sample was circa 1.2 10-12 M. This limit is equivalent to
the detection of circa 5 106 copies of DNA in a 7 l droplet or circa 7.2 1011 DNA copies in
one-liter sample.
140
T-33
Development of a bienzymatic amperometric sensor device for the
analysis of lactate
P. Giménez-Gómez, M. Gutiérrez-Capitán, C. Fernández-Sánchez, C. Jiménez-Jorquera
Instituto de Microelectrónica de Barcelona (IMB-CNM), CSIC,
Campus UAB, 08193 Bellaterra, Barcelona, Spain. ([email protected])
In this work, a comparative study to carry out the bienzymatic immobilization on gold
substrates, aiming at developing an amperometric sensor for lactate, is reported. Thin-film
gold microelectrodes fabricated with standard photolithographic techniques were used as
transducers. Two different methods were compared for the enzyme immobilization using in
both cases lactate oxidase (LOX) and horseradish peroxidase (HRP) together with
ferrocyanide as mediator to follow the cascade enzyme reaction in solution. The LOX:HRP
ratio was initially optimized from ELISA optical experiments and was found to be 1:20. The
first immobilization approach consisted of a physical adsorption carried out by dissolving
both enzymes in a PBS solution pH 7.4 and casting a 10-μL drop of this solution on the
electrode, leaving it overnight at 4ºC. The second approach was based on the formation of a
thiol self-assembled monolayer (SAM), for which the gold surface was immersed in a 4mM
3,3′-dithiodipropionic acid di(N-hydroxysuccinimide ester) (DTSP) containing dimethyl
sulfoxide (DMSO) solution for 1h at room temperature. The resulting SAM-modified gold
surface was used to covalently anchor both enzymes (see figure 1), by incubation under the
same experimental conditions used for the adsorption protocol.
The performance of the resulting sensors was tested for L-lactate detection. The calibration
curves were obtained by measuring the variation of current intensity at +0.3 V (vs. Ag/AgCl
reference electrode) generated upon the stepwise addition of L-lactate to a PBS buffer
solution, pH 7.4, containing 1mM ferrocyanide. Initial results showed that the two methods
gave rise to sensors exhibiting a similar sensitivity of ca. 2500 μA M-1 and a limit of detection
below 1x10-6 M, these being in agreement with other sensor devices found in the literature.
Nevertheless, stability tests demonstrate that the covalent method is more reliable.
Sensors will be applied to monitoring the malolactic fermentation in wine production, where
the malic acid is converted to lactic acid. The generation of this chemical species should be
strictly controlled and it could be carried out by means of a fast and easy electrochemical
method like the one shown in this work, which in turn is meant to outperform those official
methods requiring tedious preparation of many reagents.
Figure 1. Scheme of the modification of the gold surface with the SAM and the enzymes.
Acknowledgements: We acknowledge funding from the Spanish R & D National Program (MINECO
Project TEC2011-29045-C04-01).
141
T-34
Single-walled carbon nanohorns – modified electrodes as
immunosensing platforms for the sensitive determination of
fibrinogen in plasma
I.Ojeda(a), B. Garcinuño(a), M. Moreno-Guzmán(a), A. González-Cortés(a),
P. Yáñez-Sedeño(a)*, F. Langa(b), J.M. Pingarrón(a)
(a)
Department of Analytical Chemistry, Faculty of Chemistry, University Complutense of Madrid,
28040-Madrid (Spain) ([email protected]; *[email protected])
(b)
Instituto de Nanociencia, Nanotecnología y Materiales Moleculares (INAMOL),
Universidad de Castilla-La Mancha, 45071-Toledo. Spain
Single-walled carbon nanohorns (SWNHs) consist of single-wall graphene sheets having a
conical structure that are produced by laser ablation of pure graphite in absence of metallic
catalysts [1]. Both, the distinct structure and high purity, have promoted interest in the use of
this material in various applications. SWNHs tend to form quasi-spherical aggregates shaped
like a dahlia flower with a high concentration of defects and large surface area. The oxidation
treatments produce a large amount of oxygenated moieties that can be harnessed to the
incorporation of biomolecules [2]. To date only two configurations of electrochemical
immunosensors based on carbon nanohorns were found in the literature [3,4].
Fibrinogen (Fib) is a plasmatic glycoprotein produced by the liver which plays a key role in
the hemostatic system. Normal levels of Fib in human plasma range between 1.5 and 4.5
mg/mL [5]. Lower concentrations indicate the risk of bleeding and may be related to liver
diseases, whereas higher Fib levels are associated with cardiovascular diseases. Plasmatic Fib
can also be used as a biormarker for metabolic syndrome and gastric and ovarian cancer. The
determination of Fib and Fib degradation products in urine has also a great interest for the
detection of nephrotic syndrome and bladder cancer.
In this work we describe a novel design of an electrochemical immunosensor for Fib
involving the immobilization of the antigen onto activated SWNHs deposited on a screenprinted carbon electrode (SPCE), and the implementation of an indirect competitive assay
using anti-Fib labeled with horseradish peroxidase (HRP) and hydroquinone (HQ) as the
redox mediator. This simple and relatively low cost immunosensor configuration permitted
the sensitive and selective determination of Fib in plasma.
Once optimized the experimental variables, a calibration plot for Fib with a linear range
between 0.1 and 100 ȝg/mL was obtained. The limit of detection was 89 ng/mL. No
significant cross-reactivity was observed from other potentially interfering substances such as
D-dimer, IgG, BSA and hemoglobin at concentrations ten times higher than those usually
found in plasma. Furthermore, the good biocompatibility of SWNHs and the simple
preparation procedure resulted in an excellent stability of the immunoconjugates for at least
42 days. The developed immunosensor was applied to the analysis of a certified human
plasma containing 2.7 mg/mL Fib. No interference or matrix effect were found at the level of
dilution used, reaching a mean recovery of 99 ± 7%.
1. M. Yudasaka, S. Iijima, V.H. Crespi, Top. Appl. Phys., 111 (2008) 605
2. G. Pagona, N. Tagmatarchis, J. Fan, M. Yudasaka, S. Iijima, Chem. Mater. 18 (2006) 3918
3. J. Zhang, J. Lei, C. Xu, L. Ding, H. Ju, Anal. Chem. 2010, 82, 1117
4. F. Yang, J. Han, Y. Zhuo, Z. Yang, Y. Chai, R.Yuan, Biosens. Bioelectron. 55 (2014) 360
5. P. Diez, M. Gamella, P. Martinez-Ruiz, V. Lanzone, A. Sanchez, E. Sanchez, B.
Garcinuño, R. Villalonga, J. M. Pingarron, Chem.Electrochem. 1 (2014) 200
142
T-35
Influence of adenine on Zn2+ ions electroreduction in acetate
buffer
Dorota Gugała-Fekner, Jolanta Nieszporek, Dorota SieĔko, Krzysztof Nieszporek
Faculty of Chemistry, Maria Curie-Sklodowska University
Maria Curie-Sklodowska Sq. 3, 20-031 Lublin, Poland
[email protected]
[email protected]
Adenine, purine derivative is a constituent of the DNA and RNA structure and is the
subject of the studies on its effect on kinetics of Zn2+ions electroreduction on the mercury
electrode.
The Zn2+ electroreduction studies were performed by means of direct current
polarography, cyclic woltammetry and faradaic impedance.
Based on the experimental results in a pH=4 acetate buffer, it is possible to derive that
along with the increase of adenine concentration, the distance between cathodic and anodic
peaks, ǻE, increases, which was obtained by means of the cyclic voltammetry metod. Activity
resistance values RA were based on Faraday impedance method, and a decrease of standard
rate constants values in the studied electrode process were calculated. This indicated
adenine’s inhibiting effect on the electroreduction of Zn2+ ions in this buffer.
The decrease of ǻE values, with the increase of adenine concentration in a pH=6
acetate buffer as well as a decrease of the R A value and rise of standard rate constants proves
that the presence of adenine is catalytic, accelerating the Zn2+ ions electroreduction in pH 6.
A different adenine effect on the kinetics of Zn2+ ions electroreduction in acetate
buffers of various pH values might result from different forms of adenine and a different
orientation of adsorbed molecules of this compound on a mercury electrode.
143
T-36
Adsorption of guanine at the electrode – acetic buffer interface
Dorota Gugała-Fekner, Jolanta Nieszporek, Dorota SieĔko
Faculty of Chemistry, Maria Curie-Sklodowska University
Maria Curie-Sklodowska Sq. 3, 20-031 Lublin, Poland
[email protected]
Adsorption is a process occurring on the surface of bordering phases in which
individual components appear at different concentrations on the phases border, than in both
phases.
The parameters of guanine adsorption were obtained based on the following
measurements: differential capacity of the double layer at the Hg/acetate buffer pH 4
interface, potential of zero change and surface tension at this potential.
The surface tension value changes along with the zero charge potential pointed to a
guanine adsorption on the mercury electrode.
Guanines’s concentration increase caused a shift of the zero change potential towards
more negative potential testifying to the existence of a guanine aromatic chain oriented
towards the mercury electrode surface.
144
T-37
Nanocomposite Electrode for the Analysis of Chemical Oxygen
Demand in Wastewaters
Manuel Gutiérrez-Capitán, Antoni Baldi, Raquel Gómez*, Virginia García*, Cecilia JiménezJorquera and César Fernández-Sánchez
Instituto de Microelectrónica de Barcelona (IMB-CNM), CSIC. Campus de la UAB s/n, 08193 Bellaterra,
Barcelona, Spain (e-mail: [email protected]).
* ADASA Sistemas, S.A. C/ José Agustín Goytisolo 30-32, 08908 L'Hospitalet de Llobregat, Spain.
This work reports on the fabrication of carbon nanotube-polystyrene composite electrodes,
containing different inorganic electrocatalysts, namely Ni, NiCu alloy, CoO and CuO/AgO
nanoparticles, for the chronoamperometric measurement of chemical oxygen demand (COD)
in wastewaters. The different electrodes were calibrated using glucose as standard analyte,
obtaining limits of detection between 21 and 58 ppm O2 (Figure 1). However, the evaluation
of the response to real wastewaters revealed that only the COD values measured with the
CuO/AgO-based electrode were in good agreement with those obtained by an accredited
laboratory using the standard dichromate method. This nanocomposite electrode showed that
the measured values were overlapped with those ones provided by the accredited laboratory,
considering the 95% confidence intervals (Table 1). The CuO/AgO-based electrode was
eventually incorporated in a compact flow system, aiming at carrying out the analyses in an
automatic fashion. The performance of the device was very similar to that in batch. These
results demonstrate the catalytic efficiency of the CuO/AgO-based electrode for the analysis
of COD and the feasibility of the flow system for on-line monitoring of organic load in
wastewaters.
+0.6 V
Current / PA
30
20
0.1 M NaOH
500 ppm O2
50
1000 ppm O2
40
1500 ppm O2
Current / PA
40
10
0
-10
-0.4
0.1 M NaOH
106 ppm
198 ppm
394 ppm
687 ppm
987 ppm
1292 ppm
30
20
10
-0.2
0.0
0.2
0.4
0.6
+0.0 V
0
0.8
0
20
Potential / V vs. Ag/AgCl
40
60
80
100
Time / s
Fig. 1. Catalytic process and chronoamperograms obtained with the CuO/AgO-based nanocomposite electrode.
Table 1. Values of COD (in ppm O2) obtained using the CuO/AgO electrode and the standard method.
Sample 1
Sample 2
Sample 3
Sample 4
Sample 5
Sample 6
Sample 7
Sample 8
Accredited
value
269±46
165±28
178±30
152±26
201±34
590±100
221±38
172±29
CuO/AgO
electrode (n=3)
279±9
212±22
147±10
175±15
273±16
622±40
162±17
145±10
Acknowledgments: Funding from the project ITACA, IPT-20111020 (CDTI, Spain) is gratefully acknowledged.
145
T-38
Multisensor system based on electrochemical microsensors and
data fusion for classifying grape juices
Manuel Gutiérrez-Capitán, José Luis Santiago*, Jordi Vila-Planas, Andreu Llobera, Susana
Boso*, Pilar Gago*, María-Carmen Martínez* and Cecilia Jiménez-Jorquera
Instituto de Microelectrónica de Barcelona (IMB-CNM), CSIC. Campus UAB, 08193 Bellaterra, Barcelona,
Spain ([email protected])
* Misión Biológica de Galicia, CSIC. Carballeira 8, 36143 Salcedo, Pontevedra, Spain
([email protected])
A multisensor system combined with multivariate analysis was applied for the
characterization and classification of white grape juices. The proposed system, known as
hybrid electronic tongue, consisted of an array of electrochemical microsensors - seven
ISFET potentiometric sensors sensitive to pH and common ions (Na+, K+, Ca2+, Cl- and NO3-),
a conductivity sensor, a redox potential sensor, an amperometric gold microelectrode and a
microelectrode for sensing electrochemical oxygen demand - and a colorimetric optofluidic
system. The microsensors were fabricated with microelectronics technology and the
optofluidic system with soft lithography techniques. The data obtained with all these sensors
were treated with Principal Component Analysis (PCA) and Soft Independent Modeling Class
Analogy (SIMCA). For testing the system, a set of 25 white grape juices representing the
large variability of vines grown in the North-west Iberian Peninsula were studied. PCA was
used to train the system with the reference genotypes of these vines -Albariño, Muscat à Petit
Grains Blanc and Palomino- and SIMCA to study the feasibility to distinguish between
different grape juice varieties. The results show that this system differentiates with a high
resolution the three reference varieties (Figure 1). Also the PCA model constructed allows
obtaining rapid and global information about their basic characteristics: aromatic quality, total
acidity, pH, global content of sugars, colour intensity, etc. Besides, SIMCA technique allows
distinguishing between the reference varieties and the rest of grape juice samples. With a 95
% of probability, no grape juice confuses with the Albariño or Muscat à Petit Grains Blanc
models (Figure 2).
4
(A)
Muscat à Petit
Grains Blanc
3
PC 2 (25%)
2
1
0
-1
-2
Albariño
-3
-4
Palomino
-5
-4
-3
-2
-1
0
1
2
3
PC 1 (34%)
Fig. 1. Constructed PCA model
4
Sample distance to Muscat à Petit
Grains Blanc model
This system could be applied for fraud detection and it could also be a very useful tool for the
producers during wine-making according to the grape juice characteristics reported.
16
15 (A)
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0 1
p = 95%
Catalán Blanco
AB
AG
BrB G
Albariñ o
Muscat à Petit
Grains Blanc
ChD
ChB S
Bastardo
Ratiño
Moscatel Alejandría
SB Ruzo
Caíño Blanco LB
DB
Treixadura
B
BaB
M
Lado T
Blanca Mantilla
p = 95%
2
3
4
5
6
7
8
9 10 11 12
Sample distance to Albariño model
Fig. 2. Obtained SIMCA diagram
Acknowledgments: We acknowledge funding from the Spanish R & D National Program (MINECO Project
TEC2011-29045-C04-01), the INIA-MICINN National Program (Project RF2008-00002-C02).
146
T-39
SW components peak potential separation in estimation
of electrode processes kinetics
Dariusz Guziejewski, Valentin Mirceski*
Department of Inorganic and Analytical Chemistry, Faculty of Chemistry, University of Lodz, Lodz, Poland
([email protected]),
* Institute of Chemistry, Faculty of Natural Sciences and Mathematics, University “Ss. Cyril and Methodius”,
Skopje, Republic of Macedonia
Most of electrochemical methods of electrode reactions kinetics determination are based on
studying the effect of scan rate (in cyclic voltammetry) or frequency (in square wave
voltammetry) on the recorded signal (peak current, potential, half peak width and/or its
combination). Recently the splitting of the net response in SWV with alteration of amplitude
was pronounced with its effect on overall rate of electron transfer [1,2]. Here we report the
employment of amplitude effect on the SW component peak potential separation. Our first
studies were related with establishing the basic methodology in the case of surface confined
and diffusion controlled mechanism. The experimental studies were confirmed with studying
kinetics of azobenzene and hexacyanoferrate systems, respectively [3]. Here we would like to
report the application of the developed method for some of water soluble vitamins,
biologically important class of organic compounds. Electrode reaction kinetics is assessed
based on regular SW components peak potential separation as well as on amplitude-corrected
SW components peak potential separation. Electrode reaction standard rate constant can be
derived using particular working equation of user-defined electrode mechanism or with direct
fitting of theoretical simulation with experimental results.
Ackonwledgements:
We acknowledge with gratitude the support from the National Science Centre of Poland
through the grant 2011/03/N/ST4/01338.
References:
[1] V. Mirceski, M. Lovric, Electroanalysis, 1997, 9(16), 1283.
[2] V. Mirceski; S. Komorsky-Lovric, M. Lovric, Square-Wave Voltammertry: Theory and
Application; F. Scholz, Ed.; Springer Verlag: Heidelberg, 2007.
[3] V. Mirceski, D. Guziejewski, K. Lisichkov, Electrochim. Acta, 2013, 114, 667.
147
T-40
Amplitude based quasireversible maximum in electrode kinetics
determination with square wave voltammetry
Dariusz Guziejewski, Valentin Mirceski*
Department of Inorganic and Analytical Chemistry, Faculty of Chemistry, University of Lodz, Lodz, Poland
([email protected]),
* Institute of Chemistry, Faculty of Natural Sciences and Mathematics, University “Ss. Cyril and Methodius”,
Skopje, Republic of Macedonia
A quasireversible maximum is an interesting phenomenon of the whole class of surface
processes, electrode processes combined with adsorption, as well as electrode processes of
insoluble salts when investigated with square wave voltammetry technique (SWV). It is a
parabolic dependence of the square wave net peak current normalized with frequency (ΔIp/f)
on the SW frequency. This feature is a result of the current sampling procedure used in SWV,
the pulse protocol of SWV and specific properties of the surface electrode reaction [1]. Here
we report the employment of amplitude effect on the amplitude-normalized SW net peak
current. Recently the quasireversible maximum in SWV achieved with alteration of amplitude
was pronounced with its effect on overall rate of electron transfer [2]. Our first studies were
related with establishing the basic methodology in the case of a simple solution-phase
electrode reaction at a planar or spherical electrode, a solution phase electrode reaction
coupled with a reversible follow-up chemical reaction and a diffusionless surface confined
electrode reaction. The experimental studies were confirmed with studying kinetics of 2methyl-2-nitropropane [2]. Here we would like to report the application of the developed
method for other biologically important compounds. Simple experimental setup can be easily
achieved and exploited for electrode reaction kinetics determination at a fixed frequency. It
would be of exceptional importance when complex electrode reactions can be studied but
their response depends on several frequency-related kinetic parameters.
Ackonwledgements:
We acknowledge with gratitude the support from the National Science Centre of Poland
through the grant 2011/03/N/ST4/01338.
References:
[1] V. Mirceski; S. Komorsky-Lovric, M. Lovric, Square-Wave Voltammertry: Theory and
Application; F. Scholz, Ed.; Springer Verlag: Heidelberg, 2007.
[2] V. Mirceski, E. Laborda, D. Guziejewski, R. G. Compton, Anal. Chem., 2013, 85(11),
5586.
148
T-41
Application of graphene oxide-carbon paste electrode for
determination of lead in rainbow trout’s from Central Europe
Dariusz Guziejewski, Sylwia Smarzewska, Monika Skowron, Witold Ciesielski
Department of Inorganic and Analytical Chemistry, Faculty of Chemistry, University of Lodz, Tamka 12, 91403 Lodz, Poland ([email protected])
Aquatic environment pollutions caused by heavy metals are particularly
important due to their toxicity and accumulation capacity in organisms [1]. High levels of
copper, lead and iron have been stated to cause physiological changes in fish [2]. On the other
hand, fish are important part of a balanced human diet as they contain a lot of proteins,
vitamins, minerals and polyunsaturated fatty acids. According to that The Nutrition
Committee of the American Heart Association recommends to eat fish at least twice a week to
prevent cardiovascular diseases [3].
Rainbow trout (Oncorhynchus mykiss), belonging to the Salmonidae family, is
widely used as a farmed fish in many countries around the world due to its high nutritional
value and rapid growth [5]. Nevertheless, fish can be a source of contaminants such as highly
toxic heavy metal.
In the presented study content of lead in rainbow trouts samples (purchased in
local fish shops and supermarkets belonging to popular chain stores in Prague (Czech
Republic), Lodz (Poland) and Bratislava (Slovakia)) were examined.
After mineralization samples were analyzed using square wave anodic striping
voltammetry (SWASV) and graphene oxide-carbon paste electrode (GO-CPE).
The GO modified electrode exhibited stability, reproducibility and favorable
properties for quantitative lead determination. The micromolar concentrations of lead were
determined by a SWASV method at the surface of GO-CPE with RSD smaller than 5%,
recoveries in the range of 96.1 to 103.6% and LOQ, 7.24×10-9 mol L-1.
[1] D. Mendil, F. Celik, M. Tuzen, M. Soylak, Assessment of trace metal levels in some moss
and lichen samples collected from near the motorway in Turkey. J. Hazard. Mater., 166
(2009) 1344–1350.
[2] J. Tarrio, M. Jaffor, M. Ashraf, Levels of selected heavy metals in commercial fish rom
five fresh water lake Pakistan. Toxicol. Environ. Chem., 33 (1991) 133–140.
[3] P.M. Kris-Etherton, W.S. Harris, L.J. Appel, Fish consumption, fish oil, omega-3 fatty
acids, and cardiovascular disease. Circulation, 106 (2002) 2747–2757.
[5] G.A.E. Gall, P.A. Crandell, The rainbow trout. Aquaculture, 100 (1992) 1–10.
149
T-42
Voltammetric quantitative determination of disulfiram in urine
and commercial formulations
Dariusz Guziejewski, Sylwia Smarzewska, Monika Skowron, Radovan Metelka*, Witold
Ciesielski, Agnieszka Nosal-Wiercińska**
Department of Inorganic and Analytical Chemistry, Faculty of Chemistry, University of Lodz, Tamka 12, 91403 Lodz, Poland ([email protected])
*
Department of Analytical Chemistry, Faculty of Chemical Technology, University of Pardubice, 53210
Pardubice, Czech Republic
** Department of Analytical Chemistry and Instrumental Analysis, M. Curie-Skłodowska University, Lublin,
Poland
The analysis of drugs is an important field of analytical chemistry undergoing
rapid development and playing meaningful role in the cases of drug intoxication, anti-drug
control or drug therapy.
Disulfiram (Scheme 1), representative of highly significant bioactive
compounds, is a drug which has been used for decades in the aversion therapy of recovering
alcoholics.
As is well known in area of voltammetric determination of thiocarbamates the
best results were obtained on mercury electrodes. However, because of fears of mercury
toxicity there is a tendency to limit the usage of such electrodes in analytical practice.
In the presented study we propose renewable silver amalgam film electrode
Hg(Ag)FE. The application of silver amalgam allows the electrode to be used for several
months in a stable manner and enables the preservation of the properties of the mercury
electrode with very small amounts of mercury being consumed.
Scheme 1. Chemical structure of disulfiram
Using Hg(Ag)FE disulfiram was determined in bulk form (in the concentration
range from 5 x 10-8 to 5 x 10-6 mol L-1), spiked urine samples and commercial formulation
Anticol by square wave cathodic stripping voltammetry (SWCSV). Precision, repeatability
and accuracy of the method were checked. The detection and quantification limits were found
to be 1.1×10-8 mol L-1 and 3.7×10-8 mol L-1, respectively. Selectivity of the method was
examined as a influence of possible interferences.
Thin layer chromatography with an image processing software was used to
check the correctness of the elaborated method.
150
T-43
Voltammetric determination of 2-aminofluoren-9-one and
investigation of its interaction with DNA on a glassy carbon
electrode
Andrea Hájková and Vlastimil Vyskočil
Charles University in Prague, Faculty of Science, University Research Centre UNCE "Supramolecular
Chemistry", Department of Analytical Chemistry, UNESCO Laboratory of Environmental Electrochemistry,
Hlavova 2030/8, CZ-12843 Prague 2, Czech Republic ([email protected])
The studied compound – 2-aminofluoren-9-one (2-AFN) – belongs to the group of hazardous
substances with proven genotoxic effects. In the environment, its occurrence is associated
mainly with the processing and purification of natural gas in gas refineries and with the
combustion processes [1,2]. Therefore, the need of a continuous monitoring of such
environmental pollutants should be raised to the highest priority, and voltammetric techniques
are more than suitable for this purpose [3].
In this work, the voltammetric behavior of 2-AFN was investigated at a bare glassy carbon
electrode (GCE) as a function of pH to provide an overall information regarding electrochemical
transformations of 2-AFN in the negative potential region where the cathodic reduction of the
oxo group occurs. The optimal medium for its direct current voltammetric (DCV) and
differential pulse voltammetric (DPV) determination was a mixture of methanol – BrittonRobinson buffer (BR) of pH 4.0 (1:9, v/v). The calibration curves were measured in the
concentration ranges of 0.2–100 μmol L–1 (for DCV at the GCE; with the limit of quantification
(LQ) ≈ 0.4 μmol L–1) and 0.1–100 μmol L–1 (for DPV at the GCE; LQ ≈ 0.2 μmol L–1). The
practical applicability of the newly developed voltammetric methods was verified on the
direct determination of 2-AFN in model samples of drinking and river water, with the LQs in
the concentration order of 10–7 mol L–1, which are comparable to those very recently obtained
at mercury [1] and silver solid amalgam [2] electrodes.
Moreover, a novel type of an electrochemical DNA biosensor, based on the GCE and
double-stranded DNA (ds-DNA) immobilized onto the electrode surface, was used for the
investigation of the interaction between 2-AFN and ds-DNA. The predominant interaction
observed was the intercalation of 2-AFN between the DNA base pairs, causing damage to the
ds-DNA structure via the formation of a ds-DNA–2-AFN complex and double-strand breaks.
DNA-modified electrodes represent suitable tools for the in vitro investigation and detection
of supramolecular interactions between DNA and studied analytes [4].
This research was carried out in the framework of the Specific University Research (SVV
2014-260084). Financial support from the Grant Agency of the Czech Republic (Project
P206/12/G151) and from the Josef, Marie and Zdeňka Hlávkovi Talent Foundation is
gratefully acknowledged.
References
[1] A. Hajkova, V. Vyskocil, A. Danhel, J. Wang, J. Barek, Collect. Czech. Chem. Commun.
2011, 76, 1775.
[2] A. Hajkova, J. Hranicek, J. Barek, V. Vyskocil, Electroanalysis 2013, 25, 295.
[3] V. Vyskocil, J. Barek, Curr. Org. Chem. 2011, 15, 3059.
[4] V. Vyskocil, J. Labuda, J. Barek, Anal. Bioanal. Chem. 2010, 397, 233.
151
T-44
PPy-HQS composite nanowires for pH sensing application
Katarzyna E. Hnida*, Grzegorz D. Sulka
Jagiellonian University in Cracow
Department of Physical Chemistry and Electrochemistry
Ingardena 3, 30-060 Cracow, Poland
*
[email protected]
A variety of fabrication techniques can be used to form 1-D conducting polymer
nanomaterials. One of them is a electropolymerization inside porous anodic aluminum oxide
(AAO) templates. It is a very promising and powerful method to fabricate conducting
polymer structures such as nanotubes, nanowires or nanofibers. The template-assisted method
using AAO has many advantages, for example precise control of the morphology and
dimensions of fabricated nanostructures, well defined structural features of the template (pore
diameter, interpore distance, porosity or pore density), good mechanical and thermal stability,
and a well-developed preparation process. In general, the electropolymerization of a
conducting monomer has been performed at the nanochannels of AAO templates. The hard
templates were removed after polymerization in order to release 1-D conducting polymer
nanowires as it is present in Fig. 1. The potentiometric pH sensor based on PPy-HQS
nanowires were synthesized and tested.
Fig. 1. Schematic diagram for the fabrication of PPy nanowire arrays by
electropolymerization of the monomer in a porous alumina template. The home-made AAO
template was prepared by two-step anodization in 0.3 M H2C2O4 at 45 V and 20 ◦C [1].
Acknowledgments
This work was supported by the International PhD-studies programme at the Faculty of
Chemistry Jagiellonian University within the Foundation for Polish Science MPD Programme
co-financed by the EU European Regional Development Fund.
References:
[1] G.D. Sulka et al. Electrochimica Acta 104 (2013) 536– 541
152
T-45
Development of glycerol oxidase based biosensor and GC methods
for glycerol analysis in wine samples
Orsolya Hudák, Beáta Bóka and Péter Forgó
Food Science Institute, Eszterházy Károly College, Eszterházy tér 1, H-3300 Eger, Hungary
([email protected])
Glycerol is one of the major fermentation products in wines. It is mainly formed as a byproduct of wine yeast (Saccharomyces cerevisiae) glycolysis. Although glycerol, as a nonvolatile compound, has no direct impact on the aromatic characteristic of wine, high
concentrations of glycerol influences the organoleptic properties and the viscosity of the wine.
Glycerol determination is also important in clinical diagnostics, since the triacylglyceride
level in blood may give vital information concerning diseases of the cardiovascular system.
The most widespread methods of glycerol determination, such as liquid chromatography and
spectrophotometric assays are based on chemical or enzymatic reactions. These methods are
usually time consuming and require expensive instrumentation and chemicals, and welltrained experts. Biosensors can be a powerful alternative to conventional analytical methods
due to their inherent specificity, sensitivity, simplicity and quick response. Glycerol
biosensors presented previously are based on glycerol dehydrogenase or glycerol kinase coimmobilized with glycerol-3-phosphate oxidase. These biosensors characterized by
unsatisfactory selectivity and low stability, or require the application of the expensive NAD
cofactor [1]. Therefore an alternative enzyme, namely glycerol oxidase (GO) was selected for
our work. GO producer microbes (Botrytis allii and Aspergillus japonicus isolates) were
screened and a novel enzyme purification procedure was elaborated.
A. japonicus SZMC 2163 were grown on a medium supplemented with glycerol. Cell-free
extract was prepared in borate buffer, pH 10.0 by Bead-beater and purified with ammonium
sulphate fractionation, anion exchange chromatography and ultra filtration steps.
The purified glycerol oxidase enzyme was used for our final aim to develop an enzyme based
amperometric biosensor for wine analysis. The enzyme was co-immobilized on the surface of
a graphite electrode with horseradish peroxidase. This modified working electrode was used
in a wall-jet type amperometric cell together with a Ag/AgCl (0.1 M KCl) reference electrode
and a platinum auxiliary electrode. The biosensor worked in flow injection analysis system
(FIA) using a potentiostat (QuadStat 164, eDAQ, USA) and an A/D converter (e-corder,
eDAQ, USA). The effect of electrode composition, pH and potential dependence were
studied, the linear measuring range was determined.
A novel gas- chromatographic method on silyl derivatives has been applied in the quantitative
evaluation of the glycerol content of the wine samples for validation purposes.
References
[1] O. Smutok et al, (2011). Amperometric Biosensors for Lactate, Alcohols, and Glycerol
Assays in Clinical Diagnostics, Biosensors - Emerging Materials and Applications, Prof. Pier
Andrea Serra (Ed.), ISBN: 978-953-307-328-6, InTech, pp. 401 – 446.
153
T-46
Glutathione peroxidase based amperometric biosensor for
glutathione determination
Beáta Bóka, Orsolya Hudák and Levente Girán
Food Science Institute, Eszterházy Károly College, Eszterházy tér 1, H-3300 Eger, Hungary
([email protected])
Glutathione (γ-l-glutamyl-l-cysteinylglycine; GSH) is the major low molecular mass thiol in
animals, plants and even in microorganisms. During metabolism, glutathione cycles between
the reduced tripeptide form (GSH) and the oxidized disulfide form (GSSG). The glutathione
redox couple plays central roles in the defence against oxidative damage and in signalling
pathways. GSH concentration in blood could serve as biomarker of redox status. The
determination of GSH level can be useful tool for diagnosing and monitoring certain human
diseases and metabolic disorders such as cancer, neurodegenerative and cardiovascular
diseases [1].
Several methods have been proposed for the measurement of glutathione in biological
samples, most of them based on derivatization procedures. The most widely used methods are
based on different separation techniques, including high-performance liquid chromatography,
gas chromatography and capillary electrophoresis coupled with photometric, fluorimetric,
mass spectrometric or electrochemical detection [2]. These methods are time-consuming, and
require expensive instruments. Contrary to the above mentioned methods, biosensors offer a
simple, rapid and cost-effective solution.
Our aim was to develop an enzyme-based biosensor method for glutathione determination in
biological and food samples. Glutathione peroxidase (GSH-PO, EC. 1.11.1.9) catalyses the
following reaction between reduced glutathione and hydrogen peroxide or organic
hydroperoxides, like t-butyl hydroperoxide [3]:
2 GSH+ ROOH → GSSG + H2O + ROH
The GSH-PO enzyme was immobilized on the surface of a graphite electrode with
poly(ethylene glycol) (400) diglycidyl ether (PEGDGE) as crosslinker. This modified
working electrode, a Ag/AgCl (0.1 M KCl) reference electrode and a platinum auxiliary
electrode were used in flow injection analysis system. The glutathione concentration can be
calculated from the difference between the amperometric signals obtained by consecutive
injection of glutathione and GSH- t-butyl hydroperoxid mixtures.
The effect of electrode composition, pH and potential dependence were studied. Optimal
working conditions were pH=7.8 and 400 mV potential vs. Ag/AgCl. The method was
characterized by a detection limit of 5 PM and a linear measuring range of 0.01-0.200 mM.
Blood samples were analyzed by the glutathione biosensor and by reference Ellmann method
as well, and the results are compared.
References
[1] R. Masella et al, J. Nutr. Biochem. 16 (2005) 577–586.
[2] P. Monostori et al,J. Chromatogr. B, 877 (2009) 3331–3346.
[3] S. Toppo et al, Biochim. Biophys. Acta, 1790 (2009) 1486–1500.
154
T-47
High-resolution scanning electrochemical microscopy for the
characterisation of thin and thick film electrode materials
Christian Iffelsberger1, Vlastimil Vyskočil2, J. Barek2 and Frank-Michael Matysik*
1,
*University of Regensburg, Faculty of Chemistry and Pharmacy, Institute of Analytical Chemistry, Chemoand Biosensors, Universitätsstraße 31, 93040 Regensburg, Germany
([email protected])
2
Charles University in Prague, Faculty of Science, University Research Centre UNCE "Supramolecular
Chemistry", Department of Analytical Chemistry, UNESCO Laboratory of Environmental Electrochemistry,
Hlavova 2030/8, 12843 Prague 2, Czech Republic
Scanning electrochemical microscopy (SECM) is an attractive technique for the investigation
of heterogeneity in electrochemical activity of electrode surfaces. It is highly desirable to
increase the resolution of SECM studies in order to identify active (inactive) spots with a
spatial resolution in the sub-μm scale.
High-resolution SECM (HR-SECM) requires the careful preparation of very small probes. In
this study electrochemically etched platinum wires sealed in glass capillaries exhibiting active
Pt diameters down to 300 nm with RG values of about 3 were prepared [1]. Another
important aspect of HR-SECM measurements is the reliable recording of amperometric
signals down to the fA range. A home-made configuration with pre-amplification of the
primary analytical signal was implemented into the HR-SECM setup.
Several electrode materials were studied by means of HR-SECM. The improvement in
resolution for a range of probes with decreasing size is illustrated using interdigitated band
array microelectrodes with 3 μm electrode widths and 2 μm electrode gaps.
Another electrode material studied was a graphite-polystyrene composite film electrode
(CFE) [2]. The CFE is an attractive material for the development of biosensors [3]. HRSECM was applied to study the electrochemical activity of CFE surfaces in dependence on
different binder-to-carbon ratios.
References:
[1] S. Bergner, P. Palatzky, J. Wegener, F.-M. Matysik, Electroanalysis 23 (2011) 196-200.
[2] B. Yosypchuk, J. Barek, M. Fojta, Electroanalysis 18 (2006) 1126.
[3] V. Vyskočil, J. Barek, Procedia Chemistry 6 (2012) 52-59.
155
T-48
Early detection of renal disfunctions:
development of inosine-imprinted polymer
as a recognition unit
in the Extended Gate Field Effect Transistor sensors
Zofia Iskierko,1 Marta Sosnowska,1 Piyush Sindhu Sharma,1 Francis D’Souza,2
Krzysztof Noworyta,1
2
1
Institute of Physical Chemistry Polish Academy of Sciences, 44/52 Kasprzaka, 01-224 Warsaw, Poland
Department of Chemistry,University of North Texas, 1155 Union Circle, #305070, Denton, TX 76203-5017
[email protected]
S
S
S
H
S
S
N
O
H
O
N
N
S
O
O
S
S
HN
S
N
S
S
OH
S
B
OH
H
N
S
S
S
N
OH
HO
B
O
OH
S
HO
HO
Scheme 1. Structural formulas of inosine (red, bold) bis(bitiophene) derivatized functional monomers and
cross-linker monomer used for preparation of molecularly imprinted polymer (MIP).
Inosine is a purine nucleoside composed of hypoxanthine and D-ribose. It is a major
degradation product of adenosine with potent immunomodulatory and neuroprotective effects
and it has been used to relieve the symptoms of many diseases [1]. It has been also identified
as the potential early-warning biomarker of renal disfunction [2]. Due to the vital importance
of inosine, many electroanalytical methods have been developed to detect it [3] [4].
In the present work a novel recognition unit for monitoring inosine has been proposed. For
that purpose inosine-templated molecularly imprinted polymer (MIP) film has been devised
and deposited on signal transducing element. The MIP film was prepared by electrochemical
polymerization of bis(bithiophene) derivatives bearing cytosine and boronic acid substituents,
in the presence of inosine template and thiophene cross-linker. After deposition the template
removal was proved with UV-vis spectroscopy and electrochemical techniques. Subsequently,
film composition was characterized by spectroscopic techniques, and its morphology and
thickness were studied by AFM and SEM microscopy. MIP film-coated thin film transistor
was used as the chemosensor and its analytical parameters were evaluated.
References:
[1]
G. Hasko, M. V. Sitkovsky, C. Szabo, Trends Pharmacol. Sci. 2004, 25, 152.
[2]
J. F. Xiaa, Q. L. Liangb, X. P. Lianga, Y. MingWangb, P. Huc, P. Lid, G. A. Luo, J. Chromatogr. B
2009, 877, 1930.
[3]
B. Revin, A. John, Anal. Biochem. 2012, 421, 278.
[4]
L. Liu, J. Song, P. Yu, B. Cui, Electrochem. Commun. 2006, 8, 1521.
156
T-49
Chronopotentiometric Determination of Nitrophenols Using
Reticulated Vitreous Carbon Electrode
Romana Jarosova, Jiri Zima, Jiri Barek, Hana Dejmkova
Charles University in Prague, Faculty of Science, University Research Centre UNCE "Supramolecular
Chemistry", Department of Analytical Chemistry, UNESCO Laboratory of Environmental Electrochemistry,
Albertov 6, CZ-12843 Prague 2, Czech Republic ([email protected])
Nitrophenols coming from pesticide degradation products, industrial wastes, and car exhausts
are listed as priority pollutants by the US Environmental Protection Agency [1, 2]. Pesticides
based on simple nitrophenols are used as growth stimulators in agriculture [3]. Most
nitrophenols enter the environment during manufacturing and processing. Because of their
toxicity, and their potential carcinogenic, teratogenic, and mutagenic properties, it is
important to develop simple and fast methods for their determination.
Reticulated vitreous carbon (RVC) is an open-pore foam material of honeycomb structure
composed solely of vitreous carbon. It has an extraordinarily high void volume and surface
area, rigid structure and low resistance to fluid flow. RVC is a very useful electrode material,
especially where high current densities, low electrical/fluid flow resistance, the ability to hold
infused material within controlled pore sizes and minimal cell volume of the electrodes are
required [4]. The principles of RVC as a three-dimensional electrode have been reviewed [5].
The main aim of this study was finding optimal conditions for determination of o-nitrophenol
and p-nitrophenol using chronopotentiometry with RVC electrode. The optimal composition
of the supporting electrolyte and detection current was found. The conditions for the
determination of o-nitrophenol based on electrochemical reduction were optimized, and
successfully applied to the sample matrix of drinking and river water. Statistical evaluation of
the results was performed, including repeatability of the measurements and calculating the
limits of detection.
Financial support of the Grant Agency of the Czech Republic (project no. P206/12/G151),
and of Charles University in Prague (project no. SVV260084) are gratefully acknowledged.
References:
1. U.S. Environmental Protection Agency, Federal Register, 52 (1989) 131.
2. J. Luttke, V. Scheer, K. Levsen, G. Wunsch, J. N. Cape, K. J. Hargreaves, R. L.
StoretonWest, K. Acker, W. Wieprecht, and B. Jones, Atmospheric Environment, 31 (1997)
2637.
3. SRS, List of the Registered Plant Protection Products, Vol. 3, The state phytosanitary
administration, Brno, Czech Republic (2006).
4. A. Tentorino, U. Casolo-Ginelli, J. Appl. Electrochem., 8 (1978) 195.
5. D. Pletcher, F.C. Walsh, in: J.D. Genders, N.L. Weinberg (Eds.), Electrochemical
Technology for a Clearner Environment, The Electrosynthesis Co, Lancaster, New York,
1992, p. 51.
157
T-50
Porous metal film electrodes for improved trace toxic element
electrochemical analysis
Vasko Jovanovski1, Sebastiano Dal Borgo1, Samo B. Hočevar1, Hanna Sopha2, Radovan
Metelka2 and Ivan Švancara2
1
Analytical Chemistry Laboratory, National Institute of Chemistry, Hajdrihova 19, SI-1001, Ljubljana, Slovenia
Department of Analytical Chemistry, University of Pardubice, Studentská 573, CZ-53210 Pardubice, Czech
Republic
([email protected])
2
It is well-known that certain metals enable improved electrochemical detection of selected
toxic elements by formation of intermetallic compounds or alloys upon their deposition.
These metals (Bi, Sb, Sn, Au) are usually deposited on the surface of substrate electrodes
(GCE, Pt etc.) in the form of a thin film by means of electrodeposition, which offers very
good control over the amount of deposited metal. Metal film electrodes (MFEs) offer
numerous possibilities for stripping voltammetric (anodic and adsorptive cathodic stripping
voltammetry) or potentiometric methods for application in electroanalysis of selected toxic
metals (Cd, Pb, Ni, As etc.) and compounds (pesticides, pharmaceutical formulations etc.).
A very important property of MFEs used for these purposes is morphology of the deposited
metal film and associated active surface area. High active surface area increases the number
of active sites of the sensor and improves the interaction between the sensor surface and the
analyte.
In this presentation different nanosized sacrificial templates will be investigated and discussed
for electrodeposition of MFE comprising tailored porosity/morphology. Nanomaterials like
polymer particles, inorganic compounds like ZnO, ZIF-8 etc. will be casted on the surface of
the substrate electrode prior to electrodeposition of MFE. Afterwards, the template will be
carefully removed by immersing the MFE into a medium that selectively removes only the
template (organic solvent, higher or lower pH).
It is expected that this method will afford highly porous MFEs (as shown in Figure 1) with
improved electroanalytical performance for detecting trace toxic elements and also other
important compounds.
Figure 1: Porous BiFE after deposition on the GCE substrate previously modified with a layer
of polystyrene spheres (average size 500 nm) later removed with toluene.
158
T-51
A biosensor for the amperometric determination of high density
lipoprotein cholesterol based on a printed lyotropic surfactant
layer
Termeh Ahmadraji, Laura Gonzalez-Macia and Anthony J. Killard*
The Department of Biological, Biomedical and Analytical Sciences, Faculty of Health and Applied Sciences,
University of the West of England, Bristol, BS16 1QY, UK.
*[email protected]
Coronary vascular disease (CVD) is the number one cause of death worldwide. According to
a WHO report and global and regional projections of mortality and burden of disease, by
2030, the number of people dying from heart disease and stroke will increase to reach 23.3
million. Non-HDL cholesterol, determined by subtracting the high density lipoprotein (HDL)
cholesterol concentration from the total cholesterol content, has been recommended as a target
for preliminary CVD prevention. [1-3]
Electrochemical biosensor for HDL-C has been developed by combining a suitable
homogeneous assay methodology with printed electrodes having a good catalysis of hydrogen
peroxide. Each measurement was performed using a fresh and disposable screen-printed
electrode modified using inkjet printing technology. [2, 4] Polyoxyethylene tribenzylphenyl
ethers were used as a specific surfactant to solubilise HDL-C and allow the enzymatic
catalysis of HDL-C alone. The final step of measurement is typically based on the formation
of hydrogen peroxide in the presence of cholesterol esterase and cholesterol oxidase. A
generalised approach to the selective detection of HDL-C is shown schematically in the figure
below:
Apo A-I
Esterified cholesterol
ChEs
Apo C
Unesterified cholesterol
U
HDL-C selective
surfactant
Apo A-II
HDL
Triglyceride
ChOxoxi
ChOxred
HO OH
O2
Phospholipid
The effects of assay reagents such as surfactants, enzymes and serum on the electrode
behaviour were assessed amperometrically in the presence of hydrogen peroxide solutions.
The electrodes showed increase in its catalytic activity toward H2O2 in the presence surfactant
and decrease in the presence of Cholesterol oxidase and dilapidated serum. Despite the
negative effect of cholesterol oxidase and serum components on electrode behaviour, HDL-C
had a linear response between 0.5 to 4 mM, which is in the clinically relevant range.
References:
[1] Global status report on noncommunicable disaeses 2010. Geneva, World Health
Organization, 2011; [2] Ahmadraji, T. and Killard, A.J. (2013). Analytical Methods. 3
pp.3612-3625; [3] Mathers, C.D. and Loncar, D. (2006) PLoS Med, 2006, 3(11):e442; [4]
Gonzalez-Macia, L., Smyth, M.R. and Killard, A.J. (2012). Electroanalysis . 24 (3), pp.609614.
159
T-52
Printed sensors for the determination of blood ammonia
1
Niamh T. Brannelly1, Julian Hamilton-Shield2 and Anthony J. Killard*1
The Department of Biological, Biomedical and Analytical Sciences, Faculty of Health and Applied Sciences,
University of the West of England, Bristol, BS16 1QY, UK.
2
School of Clinical Sciences, University of Bristol, Bristol, BS8 1TH, UK.
*[email protected]
The determination of blood ammonia level is important in the clinical diagnosis of a number
of pathological illnesses such as hepatic encephalopathy, Reye’s syndrome, liver disease.
Conditions like these can affect brain function and are often fatal1. Pathological levels of
amomonia are usually between 10-50 μM; an elevated level of 100 μM or above indicates an
abnormality in nitrogen homeostasis. Routine blood ammonia measurement can be used to
evaluate conditions like those montioned, manage patient progress and prevent debilitating
illnesses developing2.
Selective, sensitive, point-of-care diagnostic devices for the detection of elevated blood
ammonia are being developed using a combination of screen and inkjet printing
methodologies. The conducting polymer polyaniline has been identified as an ammoniasensitive material and recently used in the development of an ammonia breath sensing
device3.
PANIH+ + NH3
ļ
PANI + NH4+
Polyaniline nanoparticulate ink is synthesised and inkjet printed onto silver screen printed
interdigitated electrodes. The device is further modified with an ammonia permeable
membrane layer and encaspsulated to exclude interferences. Current characterisation uses
electrochemical impedance spectroscopy in ammonia standards to optimise the conditions
necessary for measurement in blood.
References
1. Adeva, M. M.; Souto, G.; Blanco, N.; Donapetry, C. Ammonium metabolism in humans.
Metabolism-Clinical and Experimental 2012, 61, 1495-1511.
2. Barsotti, R. J. Measurement of ammonia in blood. J. Pediatr. 2001, 138.
3. Hibbard, T.; Crowley, K.; Kelly, F.; Ward, F.; Holian, J.; Watson, A.; Killard, A. J. Point
of Care Monitoring of Hemodialysis Patients with a Breath Ammonia Measurement Device
Based on Printed Polyaniline Nanoparticle Sensors. Anal. Chem. 2013, 85, 12158-12165.
160
T-53
A printed cholesterol biosensor based on a novel H2O2
electrocatalyst
Laura Gonzalez-Macia* and Anthony J. Killard
Department of Biological, Biomedical and Analytical Sciences, University of the West of England, Coldharbour
Lane, Bristol, BS16 1QY, UK
*[email protected]
The development of a reliable and simple point-of-care device for cholesterol determination is
essential in the clinical diagnosis of disorders such as atherosclerosis, hypertension and
cerebral thrombosis, which are generally associated with abnormal levels of cholesterol in
blood.
Electrochemical biosensors have played an important role in this field because they allow the
rapid and accurate estimation of cholesterol without the need of sample dilution and they are
suitable for mass production at low cost. Cholesterol oxidase (ChOx) is most commonly used
as the biosensing element in the fabrication of cholesterol biosensors. Hydrogen peroxide
(H2O2) is released as the end-product of the enzymatic reaction and its concentration may be
used as an indicator in the progress of the reaction.
Recently, our group has reported a significant enhancement in the catalytic activity of silver
screen printed electrodes (Ag SPEs) towards H2O2 reduction after exposure to a mixed
surfactant/salt solution.[1] The electrodes modified with a inkjet printed solution of
dodecylbenzenesulphonic acid (DBSA) and KCl exhibited up to 40-fold higher amperometric
responses to H2O2 at -0.1 V vs. Ag/AgCl, pH 6.8.
In the present work, the H2O2 formed via the enzymatic reaction of cholesterol and cholesterol
oxidase was measured using DBSA/KCl modified Ag SPEs. Encapsulated electrodes allowed
sample volumes as small as 10 μl. The feasibility of inkjet printing for the material (catalyst,
enzyme) deposition was also studied. The device was then assessed for the quantitative
determination of cholesterol in serum.
[1] L. Gonzalez-Macia, M. R. Smyth, A. Morrin and A. J. Killard, Electrochimica Acta, 2011,
56, 4146-4153.
161
T-54
!!""#"$% !!""#"$
&!''$(##)$$!$!*'##')$
$!*'$)$$$$("+#$$
$''")''#$
$('$#",-!#'')#''
! !! ''" . !# $ ''#$$'##$!"
.$$'#
#''$!'!###!$$*)'"
/$))#!##$".$
!! ' * '') * #! '$!'
!#$###!!%''#*"0
''!#'!$'$
'*$('$*!"
1 $ ## 2+3. 4#'456%$'-$#$77
#$!#$#$".$'')$
895!!''":$#!#')!#$
$#"
)'!;.$$)##*$2#$<%
*$2#<',$!).=&3%6">"6"?>%@@?@%>A@>%AAA@B'2-''
!C.=&3%6">">"%@@?@?
3D%>A@>%AA9E"
162
T-55
Hydrogel matrix doped with gold nanoparticles and grafted with
carboxyl groups for improved performance of DNA biosensors
Agata Kowalczyk, Marcin Karbarz, Barbara Wagner, Anna M. Nowicka*
Faculty of Chemistry, University of Warsaw, ul. Pasteura 1, PL-02-093 Warsaw, Poland
([email protected]),
*Faculty of Chemistry, University of Warsaw, ul. Pasteura 1, PL-02-093 Warsaw, Poland
The DNA biosensors are a powerful tool in bioanalysis [1,2]. The response of a biosensor
based on the DNA hybridization process depends strongly on the efficiency of this process.
To hybridize efficiently with the target strand the single-stranded probe DNA must have some
liberty of movement in the sensing layer. The use of a 3D gel should minimize the negative
influence of the irregularity in the distribution of the strands in the sensing monolayer and
improve the detection limit.
In the study we used the hydrogel based on N-isopropylacrylamide. The insertion of gold
nanoparticles and the grafting of carboxyl groups enabled the immobilization of two different
DNA sequences. The optimal carboxyl group content was determined to be 5 % [3]. The
detection of the hybridization process was done by using two different redox probes
covalently attached to the complementary DNA strands.
A very good agreement of the data obtained with such independent techniques as
electrochemical quartz crystal microbalance, voltammetry and ICP MS LA allowed us to
estimate the content of DNA probes in the gel and in the consequence the detection limit of
the studied sequences in the mixture. The sensor response increased linearly with logarithm of
concentration of target DNA in the range 1 10-13-1 10-6 M.
The application of the polymer matrix and appropriately selected analytical techniques
allowed us to detect two different, yet highly similar DNA sequences in their mixture.
[1]. A. Baeissa, N. Moghimi, J. Liu; RSC Adv. 2 (2012) 2981–2987.
[2]. J. Huang, Y. R. Wu, Y. Chen, Z. Zhu, X. H. Yang, C. Y. J. Yang, K. M. Wang, W. H.
Tan, Angew.Chem.Int.Ed. 50 (2011) 401–404.
[3]. A. Kowalczyk, M. Fau, M. Karbarz, M. Donten, Z. Stojek, A.M. Nowicka; Biosens.
Bioelectron. 54 (2014) 222–228.
163
T-56
Voltammetric Determination of Nitrofurantoin
at Mercury Meniscus Modified Silver Solid Amalgam Electrode
Zuzana Krejcova, Aneta Hartmanova and Jiri Barek
Charles University in Prague, Faculty of Science, University Research Centre UNCE "Supramolecular
Chemistry", Department of Analytical Chemistry, UNESCO Laboratory of Environmental Electrochemistry,
Hlavova 2030/8, 128 43 Prague 2, Czech Republic ([email protected])
Even though increased attention has been paid to the protection of our environment, an
increase in polluting with anthropogenic compounds can be observed. For example,
pharmaceuticals belong among such pollutants when they get into waste water systems. This
fact leads to increased demands for analytical methods for the determination of such
pollutants. Chromatographic methods are commonly used for this purpose [1]. However, it
has been already proved that voltammetric methods can in many cases successfully compete
with them [2].
This contribution is focused on voltammetric determination of Nitrofurantoin (NF), which is
used to treat urinary tract infection [3]. NF was chosen because of its potentially damaging
environmental effects, particularly for water ecosystems. Electrochemical behavior of NF was
studied by direct current voltammetry (DCV) and differential pulse voltammetry (DPV) using
mercury meniscus modified silver solid amalgam electrode (m–AgSAE).
Voltammetric behavior of NF was studied in cathodic region of potentials in dependence on
pH. pH 7 was selected as an optimal medium for both methods. The optimum water–methanol
ratio (9:1) was selected. In order to reduce influence of an electrode passivation, the suitable
regeneration potentials were found (0 mV and –900 mV). The optimum conditions were
found for the determination of NF in the concentration ranges from 6×10−6 to 1×10−4 mol/L
using the DCV technique, and from 4×10−6 to 1×10−4 mol/L using the DPV technique, both in
the medium of Britton–Robinson buffer–methanol (9:1). The attained limit of quantification
of NF was 1.6×10−6 mol/L for both methods.
The practical applicability of the newly developed DPV methodology was verified for the
direct determination of NF in model samples of drinking and river water in the concentration
range from 4×10−6 to 1×10−4 mol/L.
This research was carried out within the framework of the project of Academy of Sciences of
the Czech Republic (Project Open Science, CZ.1.07/2.3.00/35.0023). It was financially
supported by The Grant Agency of the Czech Republic (Project P206/12/G151).
[1] E. Stockvis, H. Rosing, J. H. Beijnen, Mass. Spectrom. Rev. 2005, 24, 6.
[2] B. Yosypchuk, J. Barek, Crit. Rev. Anal. Chem. 2009, 39, 3.
[3] E. Hammam, J. Pharmaceut. Biomed. 2002, 30, 651.
164
T-57
Mediatorless carbohydrate/oxygen biofuel cells with improved
cellobiose dehydrogenase based bioanode
V. Krikstolaityte1, P. Lamberg2, M. D. Toscano3, M. Silow3, O. Eicher-Lorka4,
A. Ramanavicius1, G. Niaura5, L. Abariute5, T. Ruzgas2, and S. Shleev2,6*
1
Department of Physical Chemistry, Faculty of Chemistry, Vilnius University, Vilnius 03225, Lithuania
2
Department of Biomedical Sciences, Faculty of Health and Society, Malmö University, Malmö 20506, Sweden
3
Novozymes A/S, Bagsvaerd 2880, Denmark
4
Department of Organic Chemistry, Center for Physical Sciences and Technology, Vilnius 01108, Lithuania
5
Institute of Biochemistry, Vilnius University, Vilnius 08662, Lithuania
6
Department of Chemical Enzymology, A.N. Bach Institute of Biochemistry, Moscow 119 071, Russia
*[email protected]
Direct electron transfer (DET) between cellobiose dehydrogenase from Humicola insolens
(HiCDH) and gold nanoparticles (AuNPs) was achieved by modifying AuNPs with a novel,
positively charged thiol N-(6-mercapto)hexylpyridinium (MHP). The DET enabled the use of
HiCDH enzyme as an anodic biocatalyst in carbohydrate/oxygen enzymatic fuel cell (EFC)
design. The biocathode was based on bilirubin oxidase from Myrothecium verrucaria
(MvBOx) directly immobilised on AuNP surface (See Fig.). The following parameters of the
EFC based on Au/AuNP/MHP/HiCDH bioanode and Au/AuNP/MvBOx biocathode were
obtained in quiescent PBS (pH 7.4) solutions containing biofuel: (i) 5 mM glucose - opencircuit voltage (OCV) of 0.65 V and the maximal power density of 4.77 μW cm-2 at operating
voltage of 0.50 V; or (ii) 10 mM lactose - OCV of 0.67 V and the maximal power density of
8.64 μW cm-2 at operating voltage of 0.50 V. The half-life operation times of the EFC was
estimated to be at least 13 h and 44 h in neutral PBS containing 5 mM glucose and 10 mM
lactose, respectively [1]. Among the advantages of HiCDH-MvBOx based EFC (i) the higher
power output with glucose as biofuel and (ii) the absence of lactose inhibition for HiCDH
based bioanode can be mentioned when compared with the previously published EFC [2].
Fig. Schematic representation of the
EFC
based
on
the
Au/AuNP/MHP/HiCDH
bioanode
and
the
Au/AuNP/MvBOx
biocathode. The proteins are shown as
grey ribbons and the carbohydrates
are shown as grey sticks. The T1
copper site and the T2/T3 copper
cluster of BOx are shown as blue
spheres, the FAD in CDH as yellow
spheres, and the heme as red spheres,
respectively.
[1] V.Krikstolaityte et al., 2014 (Submitted manuscript).
[2] X.J. Wang et al., Biosens. Bioelectron., 2012, 31, 219-225.
165
T-58
Electrochemical detection of chromosome traslocation
Dorota Kwasny, Maria Dimaki, Asli Silahtaroglu, Zeynep Tumer and Winnie E. Svendsen*
Technical University of Denmark, DTU Nanotech ([email protected]),
* Technical University of Denmark, DTU Nanotech
Cytogenetics is a study of the cell structure with a main focus on chromosomes content and
their structure. Chromosome abnormalities, such as translocations may cause various genetic
disorders and heametological malignancies. Chromosome translocations are structural
rearrangements of two chromosomes that results in formation of derivative chromosomes
with a mixed DNA sequence. The method currently used for their detection is Fluorescent In
Situ Hybridization, which requires a use of expensive, fluorescently labeled probes that target
the derivative chromosomes.
We present here a double hybridization approach developed for label-free detection of the
chromosome translocations. For specific translocation detection it is necessary to determine
that the two DNA sequences forming a derivative chromosome are connected, which is
achieved by two subsequent hybridization steps. The electrochemical impedance spectroscopy
was selected as the sensing method on a microfabricated chip with array of 12 electrode sets.
Two independent chips (Chip1 and Chip2) were used for targeting the chromosomal
fragments involved in the translocation. Each chip was differentially functionalized with
DNA probes matching the derivative chromosomes. The observed increase in the charge
transfer resistance for both chips serves as a way of detection the presence of the selected
translocation in the analyzed sample. The developed sensor was reliable and could in the
future be implemented in cytogenetic laboratories as a supplementary method for the existing
techniques.
Fig.1 Chromosome Translocation Detection - Nyquist plot – EIS measurements on bare gold (red),
Chip 1 SH-DNA 9.9 probe modified electrodes (green), Chip 2 SH-DNA 9.3 probe modified
electrodes (green) after non-complementary DNA target hybridisation (dark blue) and after Der 9
complementary DNA hybridisation (light blue). The captured Der9 was denatured for 10 min at 95 °C
and transferred manually from Chip1 to Chip2. The increase in signal on both chips indicates the
translocation presence.
166
T-59
Direct electron coupling of Humicola insolens
dehydrogenase by using structurally similar thiols
cellobiose
P. Lamberga, J. Hamit-Eminovskia, M. D. Toscanob, O. Eicher-Lorkac, G. Niaurad, T. Arnebranta,
S. Shleeva, T. Ruzgasa*
a
Department of Biomedical Sciences, Faculty of Health and Society, Malmö University, 20506 Malmö, Sweden
b
Novozymes A/S, Bagsvaerd 2880, Denmark
c
Department of Organic Chemistry, Center for Physical Sciences and Technology, Vilnius 01108, Lithuania
d
Institute of Biochemistry, Vilnius University, Vilnius 08662, Lithuania
Enzymatic fuel cells (EFCs) designed by using direct electron coupling of enzymes at
EFC electrodes are appreciated for the simplicity of construction. We have recently
described a glucose/oxygen EFC where Humicola insolens cellobiose dehydrogenase
(HiCDH) and bilirubin oxidase (BOx) act as anodic and cathodic enzymes, respectively [1]. In
this EFC construction the limiting current at the HiCDH-modified electrode was found to be
much lower than the current at the BOx-modified electrode; the EFC was, thus, limited by
the performance of bioanode. Since HiCDH is one of the very few CDH enzymes that
functions at neutral pH [2] it is highly relevant to understand how DET coupling of this
dehydrogenase can be improved.
We found that positively charged N-(6-mercapto)hexylpyridinium (MHP) enables DET
coupling of HiCDH to gold nanoparticles [1]. To understand which molecular features of
MHP that enable DET coupling of HiCDH to the gold electrode we have investigated three
additional thiols possessing similar structural features. The thiols were N-(5mercapto)pentylpyridinium (MPP), N-(6-mercaptohexyl)-4-methylpyridinium (MMP) and
mercaptohexane (MCH). The thiol-modified gold electrode surfaces were characterized by
contact angle measurements and the adsorption of HiCDH at these electrodes has been
monitored by ellipsometry. Subsequently, bioelectrocatalytic oxidation of glucose at the
electrodes has been assessed by cyclic voltammetry. The bioelectrocatalysis was studied in
PBS buffer solution (pH 7.4) containing 25 mM glucose.
Our results indicate that MHP and MPP enable very similar DET based current of
glucose bioelectrooxidation at the HiCDH modified electrodes. MHP (six-carbon) and MPP
(five-carbon) differ only by the length of the carbon chain. The MMP monolayer is more
hydrophobic since it has a methyl group at the pyridine head group. Electrode modification
by MMP gave lower bioelectrocatalytic current. MCH, a simple six-carbon hydrophobic thiol,
completely disabled DET of HiCDH at the electrode. Additional measurements are underway
for characterization of the DET kinetics of HiCDH at the thiol modified electrodes.
[1] V. Krikstolaityte, P. Lamberg, M.D. Toscano, M. Silow, O. Eicher-Lorka, A. Ramanavicius, G. Niaura, L. Abariute, T. Ruzgas,
S. Shleev, Mediatorless Carbohydrate/Oxygen Biofuel Cells with Simplified Cellobiose Dehydrogenase Based Bioanodes,
Submitted., (2014).
[2] R. Ludwig, W. Harreither, F. Tasca, L. Gorton, Cellobiose Dehydrogenase: A Versatile Catalyst for Electrochemical
Applications, Chem. Phys. Chem., 11 (2010) 2674 – 2697.
167
T-60
E-Cyclodextrin based diclofenac potentiometric sensor.
Joanna Lenik, Cecylia Wardak,
Faculty of Chemistry, Maria Curie-Skłodowska University,
3 M. Curie-Skłodowskiej Square, 20-031 Lublin, Poland
(e-mail [email protected])
The cyclodextrins (CD-s) are used in the pharmaceutical industry, food industry, clothing
industry, cosmetics industry, chemical industry and they have agricultural applications. They
are capable of interacting with a large of variety of guest molecules to form inclusion
complexes i.e. with drugs molecules [1]. Currently, in potentiometry (in sensors development)
the studies concerning use of cyclodextrins as ionophores are very new but not numerous.
Especially lipophilic cyclodextrins (by alkylation of hydroxyl group in the 2-, 3- and 6
position [2] can incorporate in plasticized PVC membrane, graphite electrode and use as
excellent ionophores.
The aim of the presented work was to the application of selected E-cyclodextrin derivativeheptakis (2,3,6–tri–o–benzoyl)-β–cyclodextrin as ionophores in a solid contact plasticized
PVC membrane electrodes selective for diclofenac . The composition of membrane phase was
following: 1.2% wt. β-cylodextrin, 0.4% wt. tetraoctylammonium chloride, 65.5% wt.
diizobutyl phthalate, 32.8% wt. PVC. The electrode shows the sensitivity -59,7r1,8 (mV
decade-1) over the linear range of 5,0x10-5 – 1,0x10-2 mol L-1 and limit of detection 1,0x10-5
mol L-1. The present electrode exhibits excellent selectivity for diclofenac over other anions
and some common drug excipients (Table 1). This electrode has a response time 20s and can
be used in the pH range 6,5-8,5. This sensor may be used in
0,51
ClO4drugs control analysis in pharmaceutical laboratories.
Salicylate
1,64
2,12
J-
2,98
H2PO4BrBenzoate
NO3Glycine
Acetate
ClPropionate
Aspartic acid
Citrate
SO42Formate
Glucose
Tartrate
3,26
SCN-
Table 1. Selectivity coefficients of diclofenac electrode
References
[1] H. Dodziuk “Cyclodextrins and their complexes” WileyVCh Verlag GmbhH & Co. KGaA, Weinheim, 2006, pp 40-47.
[2] A. Ferancova, J. Labuda Cyclodextrins as electrode
modifiers, Fresenius J. Anal. Chem. 370 (2001) 1-10.
Mannit
Oxalate
Glutamic acid
Lactose
168
4,59
5,19
5,34
5,37
5,58
5,60
5,60
5,65
5,71
5,72
5,74
5,75
5,84
5,85
6,35
6,39
6,42
T-61
Solid contact cadmium ion-selective electrode based on ionic
liquid and carbon nanotubes
Joanna Lenik, Cecylia Wardak and Malgorzata Grabarczyk
Department of Analytical Chemistry and Instrumental Analysis, Chemical Faculty, Maria Curie-Sklodowska
University, Maria Curie Sklodowska Sq 3, 20-031 Lublin, POLAND ([email protected])
Heavy metals pollution is one of the most serious environmental problems in the world.
Cadmium is extremely toxic even at low concentrations because it can bioaccumulate in
organisms and ecosystems. Cadmium causes damage of human organs such as kidneys, liver
and lungs as well as high blood pressure and destruction of red blood cells. It comes into
natural waters through waste water from electroplating industry, nickel-cadmium batteries,
phosphate fertilizers, pigments, mining and alloys. Therefore rapid and selective methods of
its determination are needed.
Potentiometric ion selective electrodes (ISEs) are known to offer an excellent low-cost tool
for the selective, sensitive and rapid determination of a vast variety of analytes in different
fields of application. The mechanism of the potential formation of ISEs with a liquid or
pseudoliquid (polymeric) membrane depends strongly on extraction and ion-exchange
processes between the aqueous and organic phases. It is known that the nature and amount of
the lipophilic additive strongly affect the response of the membrane ion-selective sensors, for
instance by reducing the membrane resistance, improving the response behavior and
selectivity.
The aim of this research was to create an ion-selective electrode sensitive to cadmium ions
with solid contact based on a PVC membrane phase containing an ionic liquid as an
additional component. Recently it was found out that ILs can replace the commonly used
lipophilic ionic additives (phenyl borates) in the membrane phase [1, 2], which are introduced
to the membrane to reduce the anion interference and to lower the membrane resistance. The
membrane phase of studied electrode contained ionic liquid: 1-butyl-3-methylimidazolium
heksafluorophosphate (BMImPF6) as lipophilic ionic additive. This ionic liquid was applied
successfully as extraction solvent for the cadmium preconcentration [3] and is soluble in
majority plasticizers. The multi-walled carbon nanotubes (MWCNTs) were used as solid
contact ion-to- electron transducer.
The proposed electrode with solid contact is characterized by the good analytical parameters:
theoretical characteristic slope, low detection limit, short response time and very long
lifetime. The electrode shows very good discriminating ability towards Cd(II) ions in
comparison with some alkali, alkaline earth, transition and heavy metal ions. Moreover it
have a stable, reproducible and reversible potential.
References:
[1] C. Wardak, J. Lenik, Sens. Actuators B 189 (2013) 52- 59
[2] C. Wardak, J. Hazar. Mater. 186 (2011) 1131-1135.
[3] E. M. Martinis, R. A. Olsina, J. C. Altamirano, R. G. Wuilloud, Talanta 78 (2009) 857862.
169
T-62
Microelectrode Biosensor for Real-time Measurement of ATP
Release from Single Cells
Xianchan Li,1 Jacqueline Keighron,1 Andrew G. Ewing 1,2,*
1
Department of Chemical and Biological Engineering, Chalmers University of Technology, Kemivägen 10, SE41296 Gothenburg, Sweden
2
Department of Chemistry and Molecular Biology, University of Gothenburg, Kemivägen 10, SE-41296,
Göteborg, Sweden
(Email: [email protected], [email protected])
Exocytosis is a vital process in neuronal communication. This is a process that has been
investigated extensively for several decades. The process of exocytosis can be summarized as
the docking of neurotransmitter-containing vesicles to the cell membrane through formation
of the SNARE complex and subsequent release of the contents by fusion of the vesicle and
cell membranes. There is growing evidence that neurons release ATP by Ca2+-dependent
exocytosis, most likely from synaptic-like microvesicles. Thus, ATP participates in the
exocytosis process, even though we are not sure of the function of this release. However,
quantification of ATP release during exocytosis is rare and its role for exocytosis is still
unclear. This is, in part, because it is difficult to measure ATP at the small levels and in small
environments as needed for these experiments. We have developed a method that uses dualenzymes (glucose oxidase and hexokinase) to detect ATP at a nanoparticle-modified
microelectrode. Glucose oxidation catalyzed by the glucose oxidase reaction produces H2O2,
and this is measured at the electrode surface. When ATP is present, glucose is partially
consumed by the hexokinase reaction decreasing the amount of H2O2 produced. The change
of current is related to the ATP concentration. The combination of careful characterization
and enzyme deposition and the use of nanoparticles have provided extremely fast response
times, and we hope to show times of 10 milliseconds. We plan to use this microelectrode to
measure the ATP release during exocytosis of PC12 cells.
170
T-63
)DVWDQGUHOLDEOHFODVVVHOHFWLYHLVRIODYRQHLQGH[GHWHUPLQDWLRQRQ
FDUERQQDQRWXEHSUHVVWUDQVIHUUHGHOHFWURGHVXVLQJPLFURIOXLGLF
FKLSV
'LDQD9LOHOD$tGD0DUWtQ0DUtD&ULVWLQD*RQ]iOH]DQG$OEHUWR(VFDUSD
'HSDUWPHQWRI$QDO\WLFDO&KHPLVWU\3K\VLFDO&KHPLVWU\DQG&KHPLFDO(QJLQHHULQJ8QLYHUVLW\RI$OFDOD
$OFDOiGH+HQDUHV0$'5,'6SDLQGLDQDYLOHOD#XDKHV
'HSDUWPHQWRI$QDO\WLFDO&KHPLVWU\3K\VLFDO&KHPLVWU\DQG&KHPLFDO(QJLQHHULQJ8QLYHUVLW\RI$OFDOD
$OFDOiGH+HQDUHV0$'5,'6SDLQDOEHUWRHVFDUSD#XDKHV
5HOHYDQW OLWHUDWXUH KDV UHFHQWO\ GHPRQVWUDWHG WKDW PLFURIOXLGLF PHHWV QDQRPDWHULDOV PDNLQJ
WKH PLFUR DQG QDQRWHFKQRORJLHV D JRRG FRPELQDWLRQ ZLWK SOHQW\ RI DQDO\WLFDO SRVVLELOLWLHV
&RPPRQO\ WKH EXLOGLQJ RI FDUERQ QDQRWXEHV &17VEDVHG GHWHFWRUV IRU PLFURIOXLGLF
VHQVLQJ KDV EHHQ FDUULHG RXW XVLQJ WZR DSSURDFKHV L WKLQILOP FRDWLQJ DQG LL EXLOGLQJ
&17VSRO\PHUFRPSRVLWHV
$OWHUQDWLYHO\WRWKRVHDSSURDFKHVUHFHQWO\ZHKDYHSURSRVHGQRYHOSUHVVWUDQVIHUUHGFDUERQ
QDQRWXEHV HOHFWURGHV 37(V RQ SRO\PHWK\OPHWKDFU\ODWH 300$ VXEVWUDWHV IRU
HOHFWURFKHPLFDO PLFURIOXLGLF VHQVLQJ 6LQJOHZDOOHG FDUERQ QDQRWXEH SUHVVWUDQVIHUUHG
HOHFWURGHV6:37(VDUHQHZGLVSRVDEOHHOHFWURGHVZKHUHFDUERQQDQRWXEHVDFWDVH[FOXVLYH
HOHFWURFKHPLFDOWUDQVGXFHUEHLQJDQH[FHOOHQWDOWHUQDWLYHWRFRPPRQDSSURDFKHVLQWKHILHOG
,Q WKLV ZRUN WKHVH SLRQHHULQJ 6:37(V FRXSOHG WR PLFURIOXLGLFV FKLSV 0&V KDYH EHHQ
HPSOR\HGWRGHYHORSWKHLUILUVWUHDODSSOLFDWLRQ$FODVVVHOHFWLYHHOHFWURFKHPLFDOLVRIODYRQH
LQGH[ GHWHUPLQDWLRQ KDV EHHQ SURSRVHG IRU IDVW DQG UHOLDEOH TXDOLWDWLYH DQG TXDQWLWDWLYH
DVVHVVPHQW RI FODVVLVRIODYRQH EDVHG RQ WKH FRPLJUDWLRQ RI WKH WRWDO JO\FRVLGHV 7* DQG
WRWDO DJO\FRQHV 7$ LQ OHVV WKDQ V ZLWK YHU\ JRRG LQWUD6:37(V UHSHDWDELOLW\
56'V”Q DQGLQWHU6:37(VUHSURGXFLELOLW\56'V”Q 7KHVHQRYHO6:37(VDUHHQWHULQJZLWKLPSRUWDQWUROHVLQWRWKHPLFURDQGQDQRWHFKQRORJLHV
VFHQHVH[SDQGLQJQHZIURQWLHUVLQWKHIRRGDQDO\VLVDQGKHDOWKILHOG
>@'9LOHOD-*DUy]$&ROLQD0&*RQ]iOH]DQG$(VFDUSD³&DUERQQDQRWXEHVSUHVV
WUDQVIHUUHGRQ300$VXEVWUDWHVDVH[FOXVLYHWUDQVGXFHUVIRUHOHFWURFKHPLFDOPLFURIOXLGLF
VHQVLQJ´$QDO\WLFDO&KHPLVWU\
>@ ' 9LOHOD $ 0DUWtQ 0& *RQ]iOH] $ (VFDUSD ³)DVW DQG UHOLDEOH FODVVVHOHFWLYH
LVRIODYRQH LQGH[ GHWHUPLQDWLRQ RQ FDUERQ QDQRWXEH SUHVVWUDQVIHUUHG HOHFWURGHV XVLQJ
PLFURIOXLGLFFKLSV´$QDO\VW'2,&$1.
171
T-64
Magnetic beads based immunosensor for fumonisin B1
detection using modified CSPEs
J.Adrian Jodra, Miguel A. Lopez and Alberto Escarpa
Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering University of Alcala,
Alcalá de Henares (MADRID), Spain, 918854971 ([email protected])
Mycotoxin analysis is a highly concern area included in food safety, since they are
potent toxins causing a wide range of actions on animals and humans health.
Considered as secondary metabolites produced by filamentous fungi (F. vertillioides, F.
proliferatum) fumonisins have been classified as carcinogenic, nephrotoxic, and other
important diseases in animals and humans. Due to these adverse effects and its
appearance as contaminant in various agroalimentary products such as cereals and
beverages, sensitive and specific methods for fast, reliable and low cost detection are
compulsory.
Electrochemical immunosensors combine the inherent selectivity of the antigenantibody interaction with the well-known advantages of electrochemical detection as
high sensitivity, low cost, or in-situ measurements. In this work, we have developed an
electrochemical immunosensor involving magnetic beads as oriented antibody
immobilization support and disposable CSPEs for sensitive, fast and reliable fumonisin
B1 determination (Fig. 1). After optimization of the main parameters affecting the
performance of the immunosensor, a remarkable limit of detection of 0.577 PgL-1, a
very good precision (RSD<9%, n=5) and excellent accuracy, evaluated through the
analysis of a maize certified reference material, were obtained. Furthermore, using a
simplified calibration protocol, relevant solid and liquid food samples such as maize
corn and maize-containing beer were analysed showing the excellent suitability of the
proposed immunosensor as disposable analytical tool in food safety diagnosis.
Acknowledgements: Financial support from the Spanish Ministry of Economy and Competitiveness
CTQ2011-28153 (A.E.) and the AVANSENS program from the Community of Madrid (P2009/PPQ1642) are acknowledged. D. Adrián Jodra acknowledges the FPI fellowship received from the Spanish
Ministry of Economy and Competitiveness.
E
BEAD/PROTEING
ANTIBODY
FB1
FB1ͲHRP
Fig. 1: Schematic representation of the electrochemical immunosensor strategy.
172
T-65
Amperometric Biosensor Based on Horseradish Peroxidase:
Effects of Various Mediators and Nanoparticles
Pavla Macíková, Jana Skopalová, Jan Petr*
Department of Analytical Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, 771 46 Olomouc,
Czech Republic ([email protected])
* Regional Centre of Advanced Technologies and Materials, Department of Analytical Chemistry, Faculty of
Science, Palacký University, 17. listopadu 12, 771 46 Olomouc, Czech Republic
The sensitive detection of hydrogen peroxide plays a significant role in pharmaceutical,
clinical and industrial sphere. Among techniques such as titration, spectrometry,
chemiluminiscence and electrochemistry, enzyme-based biosensors hold attention due to their
convenience, high sensitivity and selectivity. Horseradish peroxidase (HRP) is an important
heme-containing enzyme which catalyses the oxidation of a wide variety of substrates by
H2O2 [Liu at al.].
In this work a hydrogen peroxide amperometric biosensor based on HRP with the effects of a
polymer, several mediators and various nanoparticles has been studied. Two electrode
materials (spectral carbon and screen printed carbon microelectrode) were proved. We find
out that an addition of a polymer polyethyleneglycol diglycidyl ether (PEGDE) increased the
signal of H2O2. Then, an influence of three mediators (paraquat, osmium tetroxide on poly(4vinylpyridine) and ferrocene) was investigated. The ferrocene mediator provided the best
results. We examined various concentrations of ferrocene and the best H2O2 response was
observed with the ferrocene concentration 2 g/L. Finally, an influence of several nanoparticles
such as graphene, gold nanoparticles and nanowires, iron nanoparticles, iron oxide
nanoparticles, diamond nanoparticles and carbon quantum dots were tested. An influence of
different procedures of biosensor preparation was investigated such as a deposition of single
layers of the modifiers or a mixture of HRP, PEGDE and nanoparticles. The biosensors were
tested using amperometry and cyclic voltammetry in buffered aqueous solution with
0.1 μmol/L phosphate buffer pH 7.4. Limits of detection were achieved in tenths of μmol/L
especially using graphene nanoparticles.
Reference
Liu, X. J., Luo L. Q., Ding Y., Xu Y., Li F.: J Solid State Electrochem 15 (2011) 447–453.
Acknowledgements
The authors gratefully acknowledge the financial support by the Operational Program Research and
Development for Innovations - European Regional Development Fund (Project CZ.1.05/2.1.00/03.0058) and by
the Operational Program Education for Competitiveness – European Social Fund (Project
CZ.1.07/2.3.00/20.0018). The work has been also supported by the project of Palacký University in Olomouc
IGA_PrF_2014031 and the Czech Science Foundation project P206/12/1150.
173
T-66
$QRGLFR[LGDWLRQRIWULEURPRSKHQROLQDOFRKRODTXHRXV
PHGLD
(YD0DUNRYi3DYOD0DFtNRYi-LWND6RXþNRYi+DQDâYHFRYi-DNXE7iERUVNê-DQD
6NRSDORYi3HWU%DUWiN
'HSDUWPHQWRI$QDO\WLFDO&KHPLVWU\5HJLRQDO&HQWUHRI$GYDQFHG7HFKQRORJLHVDQG0DWHULDOV)DFXOW\RI
6FLHQFH3DODFNê8QLYHUVLW\OLVWRSDGX2ORPRXF&]HFK5HSXEOLFHPDLOPDUNRYDH#HPDLOF]
(OHFWURFKHPLFDO R[LGDWLRQ RI SKHQROV DQG LWV GHULYDWLYHV LV UHPDUNDEOH FRPSOH[ SURFHVV
5HDFWLRQSDWKZD\VGHSHQGRQYDULRXVH[SHULPHQWDOFRQGLWLRQVVXFKDVS+HOHFWURGHPDWHULDO
SRWHQWLDO DQG RQ SKHQRO VXEVWLWXWLRQ DQG FRQFHQWUDWLRQ >@ 3KHQR[\ UDGLFDOV DUH IRUPHG LQ
WKH ILUVW VWHS RI HOHFWURR[LGDWLRQ RI SKHQROV 7KHVH UDGLFDOV FDQ EH IXUWKHU R[LGL]HG WR
TXLQRQHV RU WKH\ FDQ UHDFW WR HWKHU DQG TXLQRQHW\SH GLPHULF SURGXFWV >@ )XUWKHU
R[LGDWLRQRIWKHGLPHUVFDQOHDGWRIRUPDWLRQRISRO\PHUVWKDWSDVVLYDWHWKHHOHFWURGHVXUIDFH
6WUXFWXUH RI WKH SURGXFWV RI SKHQROV HOHFWURR[LGDWLRQ GHSHQGV RQ UHDFWLRQ PHGLXP
)RUPDWLRQ RI &2& ERQGV LV W\SLFDO IRU R[LGDWLRQ RI SKHQROV LQ DONDOLQH DTXHRXV VROXWLRQ
ZKLOHWKH&&FRXSOLQJSUHYDLOVLQDFLGLFDTXHRXVVROXWLRQV>@
7ULEURPRSKHQRO 7%3 LV UDWKHU DEXQGDQW FRQWDPLQDQW LQ WKH HQYLURQPHQW >@ 7KH
DQWKURSRJHQLFSURGXFWLRQRIWKLVFRPSRXQGDSSDUHQWO\SUHYDLOVEXWWKHQDWXUDOVRXUFHVDUHQRW
H[FHSWLRQV 7%3 LV XVHG DV IXQJLFLGH DQG DQ LQWHUPHGLDWH LQ WKH SURGXFWLRQ RI RWKHU
EURPLQDWHG IODPH UHWDUGDQWV>@ ,Q UHFHQW \HDUV WKHUH LV LQFUHDVH LQWHUHVW LQ H[SORULQJ RI
R[LGDWLRQ PHFKDQLVP RI EURPLQDWHG SKHQROV DQG SURGXFWV +RZHYHU GLUHFW HOHFWURFKHPLFDO
R[LGDWLRQRIWKHVHFRPSRXQGVLVPHQWLRQHGUDUHO\>@
7KH DLP RI WKLV ZRUN LV WR LQYHVWLJDWH SURGXFWV RI HOHFWURFKHPLFDO R[LGDWLRQ RI 7%3 LQ
DOFRKRODTXHRXV YY VROXWLRQV 2[LGDWLRQ RI 7%3 ZDV SHUIRUPHG RQ SODWLQXP JDX]H
HOHFWURGH LQ WKH SUHVHQFH RI YDULRXV DOFRKROV DV PHWKDQRO HWKDQRO SURSDQRO EXWDQRO
3URGXFWV RI HOHFWURFKHPLFDO R[LGDWLRQ ZHUH DQDO\]HG DQG LGHQWLILHG E\ *&06 6HYHUDO
GLIIHUHQWW\SHVRIPRQRPHULFDVZHOODVGLPHULFDONR[\GHULYDWLYHVKDYHEHHQIRXQGDPRQJ
WKHSURGXFWVDQGWKHLUVWUXFWXUHVKDYHEHHQSURSRVHG
,Q DGGLWLRQ WR SUHYLRXVO\ LGHQWLILHG VHULHV RI GLEURPRDONR[\SKHQROV PRQRPHULF
VWUXFWXUHV FRUUHVSRQGLQJ PRVW SUREDEO\ WR UHVSHFWLYH WULEURPRDONR[\F\FORKH[D
GLHQRQHVDQGGLEURPRDONR[\F\FORKH[HQHGLRQHVZHUH IRXQG %\ DQDORJ\ WR
SUHYLRXVO\ LGHQWLILHG PRQRPHULF DONR[\GHULYDWLYHV VHULHV RI GLPHULF GLEURPR
GLEURPRDONR[\SKHQR[\SKHQROV ZDV VXJJHVWHG DQG VXSSRVHGO\ LGHQWLILHG LQ UHVSHFWLYH
FKURPDWRJUDPVDVZHOO
5HIHUHQFHV
>@0)HUUHLUD+9DUHOD507RUUHVL*7UHPLOLRVL)LOKR(OHFWURFKLP$FWD
>@=(åHUVNLV=-XV\V-$SSO(OHFWURFKHP
>@=(åHUVNLV=-XV\V-$SSO(OHFWURFKHP
>@3+RZH6'REVRQ+00DOFROP7ULEURPRSKHQRODQG2WKHU6LPSOH%URPLQDWHG3KHQROV
&RQFLVH,QWHUQDWLRQDO&KHPLFDO$VVHVVPHQW'RFXPHQW:RUOG+HDOWK2UJDQL]DWLRQ*HQHYD
>@(0DUNRYi36P\VORYi30DFtNRYi-6NRSDORYi3%DUWiN&KHP/LVW\
$FNQRZOHGJHPHQWV
7KH DXWKRUV JUDWHIXOO\ DFNQRZOHGJH WKH ILQDQFLDO VXSSRUW E\ WKH 2SHUDWLRQDO 3URJUDP 5HVHDUFK DQG
'HYHORSPHQWIRU,QQRYDWLRQV(XURSHDQ5HJLRQDO'HYHORSPHQW)XQG3URMHFW&=DQGE\
WKH 2SHUDWLRQDO 3URJUDP (GXFDWLRQ IRU &RPSHWLWLYHQHVV ± (XURSHDQ 6RFLDO )XQG 3URMHFW
&= 7KH ZRUN KDV EHHQ DOVR VXSSRUWHG E\ WKH SURMHFW RI 3DODFNê 8QLYHUVLW\ LQ
2ORPRXF,*$B3U)BDQGWKH&]HFK6FLHQFH)RXQGDWLRQSURMHFW3
174
T-67
Concerted Determination of the Hydrogen Atom and Electron
Transfer Capacity of Lipid Soluble Reducing Agents
Matteo Scampicchio, Solomon Mengistu Lemma, Marco Mason and Andrea Bulbarello*
Free University of Bolzano, Piazza Università 5, 39100 Bolzano ([email protected])
*DSM Nutritional Products Ltd. Nutrition Innovation Center Research and Development Forms and Application,
CH-4303 Kaiseraugst, Switzerland.
The generation of free radicals by 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) is
used in the oxygen radical absorbance capacity assay (ORAC) to test the antioxidant capacity
of bioactives and antioxidants [1]. In this assay, AAPH triggers the formation of reactive
oxygen species (ROS), which rapidly quench the signal of a fluorofore (e.g. fluorosceine). If
antioxidants are present, the quenching of the fluorofore is delayed and a more stable
fluorescence signal is obtained [2]. The increased stability of the fluorescence is proportional
to the antioxidant capacity of the antioxidant. This is the result of the capability of a redox
species – the antioxidant – to transfer either protons or electrons to a radical [3].
However, ORAC assay is not free from drawbacks. The assay suffers from turbid samples or
emulsions. Furthermore, the assay cannot be run with organic solvents. This specific pitfall
precludes, in principle, its use with liposoluble bioactives and liposoluble antioxidants. A
further limitation of ORAC is that it measures the antioxidant capability of bioactives in
relation to a synthetic fluorofore (fluorosceine). Thus, ORAC determines the antioxidant
activity of bioactives only indirectly, in relation with an artificial substrate.
The poster describes a method based on square wave voltammetry able to evaluate either the
electron transfer or the hydrogen atom transfer of lipid soluble antioxidants such as dl-atocopherol, BHT, ethoxyquin and retynil acetate. The electron transfer capacity was evaluated
by the peak current, peak potential and the area under the anodic wave, whereas the hydrogen
atom transfer capacity by the kinetic rate of the reaction between antioxidants and 2,2Azobis(2-methylpropionamidine) dihydrochloride (AAPH). The results indicate that
ethoxyquin and tocopherol have the highest SET and HAT capacity. However, HAT capacity
of tocopherol, BHT and retinyl acetate depend on the concentration. The approach has the
advantage to assess HAT and SET capacity of lipid soluble antioxidant in a single concerted
protocol.
[1] G. Cao, H. Alessio, R. Cutler, Free Radical Biology And Medicine. 1993, 14, 303-311.
[2] H. Wang, G. Cao, R. Prior, J. Agric. Food Chem. 1996, 44, 701-705.
[3] F. Di Meo, V. Lemaur, J. Cornil, R. Lazzaroni, J. Duroux, Y. Olivier, P. Trouillas, Journal
Of Physical Chemistry A. 2013, 117, 2082-2092.
175
T-68
Modification of gold surface with magnetic nanoparticles for
preparation of sensitive hemoglobin biosensor
Edyta Matysiak, Anna M. Nowicka
Faculty of Chemistry, University of Warsaw, Pasteura 1, PL 02-093 Warsaw, Poland;
[email protected]
The application of magnetic nanoparticles and an external magnetic field gave a
possibility of enhanced transport of oxygen molecules and iron complexes to the electrode
surface [1,2]. This effect led to an increase in the analytical signal. Next we turned to
hemoglobin. Hemoglobin plays a very important role in the living organisms. This molecule
is an oxygen carrier in the human body. Also, hemoglobin is a blood protein which contains
iron. Iron(III) in hemoglobin is a paramagnetic species.
Here we present a simple biosensor for hemoglobin detection. The surface of AuEQCM electrode was modified with magnetic nanoparticles (carbon-encapsulated iron
nanoparticles, Fe@C). Hemoglobin solutions were prepared in PBS of pH 6.0. As the first
step the optimization of the thickness of Fe@C layer was done. The presence of nanomagnets
on the electrode surface and the application of an external magnetic field allowed us to
increase substantially the hemoglobin flux to the electrode surface. The enhancement of the
hemoglobin transport to the electrode surface and the interactions of the analyte with Fe@C
were studied using electrochemical quartz crystal microbalance, cyclic voltammetry and
differential pulse voltammetry. The detection limit was estimated to be circa 0.2 nM. The
stability and reproducibility of the analytical signals were very good.
[1] A.M. Nowicka, A. Kowalczyk, M. Bystrzejewski, M. Donten, Z. Stojek; Electrochem. Commun. 20, 2012, 4.
[2] A.M. Nowicka, A. Kowalczyk, M. Bystrzejewski, M. Donten, M.L. Donten, Z. Stojek; Electrochim. Acta,
http://dx.doi.org/10.1016/j.electacta.2013.08.027.
176
T-69
Fast capillary electrophoresis in short capillaries with
electrochemical detection
Jonas Mark, Frank-Michael Matysik*
University of Regensburg, Institute for Analytical Chemistry, Chemo- and Biosensors, Universitätsstr. 31, 93053
Regensburg, Germany ([email protected])
Research on separations using short conventional capillary pathways at high field strengths is
receiving increased interest due to the possibility of realizing rapid and inexpensive analytical
determinations with potential for high-throughput applications. The concept can be especially
useful for monitoring reaction kinetics or for implementation into multidimensional systems.
Coupling the short capillaries to electrochemical detection offers the possibility to construct
highly miniaturized and independent analytical devices as power consumption and component
size are comparatively low [1, 2].
A system for combining the advantages of short capillary electrophoresis with
electrochemical detection within an automated device is presented. An amperometric detector
is implemented on this very short separation pathway. As the injection plug length has to be
kept at a narrow level, different injection protocols are investigated. In addition to that, a
range of different capillary inner diameters (5 to 50 μm) were tested and evaluated for
applicability. This methodical approach can be the basis for the construction of a
miniaturized, fully portable device with point-of-care applicability.
References:
[1] F. Opekar, P. Coufal, K. Stulik, Chem. Rev. 2009, 109, 4487-4499.
[2] F.-M. Matysik, Anal. Bioanal. Chem. 2010, 397, 961-965.
177
T-70
New coulometric detector with renewable working material for
flow injection analysis and HPLC
Jan Mika, Jiri Barek, Jiri Zima and Hana Dejmkova*
Charles University in Prague, Faculty of Science, University Research Centre „Supramolecular Chemistry“,
Department of Analytical Chemistry, UNESCO Laboratory of Environmental Electrochemistry, Albertov 6,
CZ–12843 Prague 2, Czech Republic ([email protected]). *[email protected]
This work attempts to introduce newly developed flow-through coulometric detector with
renewable working material based on glassy carbon spherical microparticles. This system was
developed mainly for determination of strongly passivating analytes. Construction of the
detector and the renewal of the working material are described. Determination of potassium
ferrocyanide and hydroquinone by flow injection analysis (FIA) were used for testing of the
basic electrochemical parameters of the detector.
Tested detector was used for development of new electrochemical determination methods of
thymol and sulfamethizole in pharmaceutical preparations by FIA and HPLC, respectively.
Both these analytes strongly passivated working material during their determination and so
the working material had to be replaced periodically after every 6 injections of thymol and 3
injections of sulfamethizole. Thymol has antibacterial and antiseptical properties and it is
used against diseases of respiratory tract or in stomatology [1,2]. Sulfamethizole is
sulfonamide antibiotic commonly used as therapy of urinary tract, especially against Escheria
coli [3]. Optimal conditions of determination of both analytes were found. Optimal carrier
solution for thymol determination was Britton-Robinson (B-R) buffer pH 10 and other
optimal conditions were: flow rate 0.6 mL min–1, detection potential +1.1 V and injected
volume 50 μL. In the case of sulfamethizole, ten times diluted B-R buffer pH 3 : methanol
(70:30, v/v) was determined as optimal mobile phase. Flow rate 0.8 mL min–1 and detection
potential +1.6 V were set as optimal conditions of determination. Calibration dependences
were linear from 100 μmol L–1 to quantification limits, which took value 0.97 μmol L–1 for
thymol and 0.040 μmol L–1 for sulfamethizole.
Content of thymol and sulfamethizole were determined under the optimal conditions in
Septolete D (tablets) and Micturol® Sedante Fuerte (tablets), respectively. Results were
consistent with values achieved by HPLC with spectrophotometric detection.
Acknowledgements
This work was performed in the framework of Specific university research (SVV). Financial
support from the Grant Agency of Charles University (project no. 84213/2013) is gratefully
acknowledged.
References:
[1] P. Lo Cantore, V. Shanmugaiah, N.S. Iacobellis, J. Agric. Food Chem., 57 (2009) 94549461.
[2] A. Chevallier, The encyclopedia of medicinal plants, DK Pub., 1996.
[3] M.B. Kerrn, N. Frimodt-Moller, F. Espersen, Antimicrobial Agents and Chemotherapy, 47
(2003) 1002-1009.
178
T-71
Mediated amperometric monitoring of DT-diaphorase induction
in cancer cells – tool for screening phytotherapeutical drugs
Lucia Montini, Valeria Tilli, Claudia Caviglia, Marco Biagi, Daniela Giachetti, Kinga Zór,
Arto Heiskanen, Jenny Emnéus*
Section of Pharmaceutical Biology, University of Siena, Italy and Department of Micro- and Nanotechnology,
Technical University of Denmark, Lyngby, Denmark ([email protected])
*Dept. of Micro- and Nanotechnology, Technical University of Denmark, Lyngby, Denmark
Chemotherapy has been used as a treatment of cancer during the past 60 years. However,
chemotherapeutic drugs are well known for undesirable side effects due to unspecificity of the
drugs and genetic variation between patients. One approach to eliminate unspecificity is
targeted chemotherapy [1] using prodrugs, which are selectively activated in tumor tissue
without affecting healthy tissues. Activation of many prodrugs is achieved through
intracellular reduction by cytosolic redox enzymes (bioreductive activation), the most
important of which is DT-diaphorase. In many type of cancer cells, DT-diaphorase is
naturally overexpressed, whereas it is not the case in healthy tissues [2]. There are, however,
cancer cells that do not possess a significant DT-diaphorase activity. Intensive research is
ongoing to identify synthetic or naturally occurring chemical species that can selectively
induce DT-diaphorase activity in cancer cells to widen the applicability of chemotherapeutic
drugs relying on bioreduction [3]. Traditional screening assays based on enzyme activity
determination in cell lysates are very labour-intensive and time consuming.
Here, we present optimization of a mediated amperometric assay for monitoring induction of
DT-diaphorase activity in living cancer cells as the first demonstration of the technique on
living human cells. Detection is conducted based on the application of the double mediator
system menadione/ferricyanide (Fig. 1). In our previous studies, these mediators have been
applied successfully for screening of genetic modifications of S. cerevisiae cells in relation to
cellular redox activity [4,5]. Menadione, a lipophilic quinone capable of entering the
intracellular environment, is reduced by cytosolic redox enzymes, e.g., DT-diaphorase. Upon
diffusing back to the extracellular environment, the reduced form of menadione delivers the
electrons to ferricyanide, which is reoxidized at an electrode. The recorded current is an
indication of changes in cellular reducing capacity. The project aims at assay automation
using a modular microfluidic cell culture device analogously with our previous studies on S.
cerevisiae [6,7].
Figure 1. The effect of menadione concentration and
assay time on cellular reducing capacity in HeLa cells
References:
[1] Rooseboom M., et al. Pharmacol. Rev. (2004)
56, 53.
[2] Danson S., et al. Cancer Treatment Rev. (2004)
30, 437.
[3] Begleiter A., et al. Meth. Enzymol. (2004) 382,
320.
[4] Heiskanen A., et al. Electrochem. Coomun.
(2004) 6, 219.
[5] Heiskanen A., et al. Anal. Biochem. (2009)
384, 11.
[6] Zór K., et al. μTAS 2011, Vol 1, 1532.
[7] Heiskanen A., et al. Anal. Bioanal. Chem.
(2013) 405, 3847.
179
T-72
! ! ! ! !!"
#! ! $%&&&'()))*
! ! ! ! !!"
#! ! $
+,!
- ! . / 0! / 00 )
+0! 0 / ! 0, /
!)#1!! )
/ 0 ! , ! 1! /! / ! !
200 !, ,)#/20 !!! 00
!! 0 , 0 !, ! , ! !!! 3
!,!!0 )4#, !, ! , ! ,56 , ) # / , %78&* ! ! ! ,) # 200 ! , / 0!! 0 ,56 / !0 ! 56 ! , !
,56 /) 9 0 / 0 ! , ! 1!
/,!!,!)
!!!,/,,, !%: *
, ! 00 % *) / ! !! ,%";'*5 %
*)
/ ! !! %";'*5 %*) 10<
05''/=5;54/=)
:!
4)))
!''>?')
180
T-73
Electroanalytical applications of pyrolyzed photoresist carbon
electrodes in aprotic solvent: from bilirubin electrochemistry to
superoxide electrogeneration
Ligia Maria Moretto1, Morena Silvestrini1, Andrea Mardegan1,2, Paolo Scopece2 and Paolo
Ugo1
1
Department of Molecular Sciences and Nanosystems, University Ca’ Foscari of Venice, Santa Marta 2137,
30123 Venice, Italy ([email protected])
2
Veneto Nanotech, via delle Industrie 5, 30175 Venice-Marghera, Italy
Pyrolyzed photoresist carbon electrodes (PPCEs) are fabricated by photolithographic microfabrication and pyrolysis of an epoxy-based photoresist named SU-8 [1]. In this work, the
results of the voltammetric, spectroscopic and diffractometric characterization of the PPCEs
are reported and discussed. In addition, their electrochemical performances are investigated,
for the first time, in aprotic solvent namely dimethyl sulfoxide, used here as medium to revisit
the electrochemical behavior of bilirubin (BR) by cyclic voltammetry. BR has been chosen as
target molecule because of its clinical importance in several diseases [2]. Indeed, BR can be
toxic under certain conditions, especially in neonates. On the other hand, a mild
hyperbilirubinaemia may have a protective effect against ischemic cardiovascular diseases
and tumour development [3].
PPCE presents good electrochemical performances comparable with those of a conventional
glassy carbon electrode (GCE), allowing to detect multiple electro-oxidation and electroreduction mechanisms of BR, thanks to the wide potential window accessible in the chosen
experimental conditions (Fig. 1).
5
Current / PA
4
3
2
1
0
-1
-2
-3
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
Potential / V vs Pt-pseudo
Figure 1. Cyclic voltammogram of 1 mM BR recorded at PPCE in
0.1 M TBABF4, DMSO solution. Scan rate 10 mV s-1.
Finally, the possibility to use PPCEs for the electrogeneration of the superoxide anion (O2-•)
by simple electrochemical reduction of dissolved oxygen is evaluated in detail. The additional
study of the reactivity of O2-• with BR allows the evaluation and confirmation of the
scavenging properties of BR.
References
[1] A. Mardegan, R. Kamath, S. Sharma, P. Scopece, P. Ugo, M. Madou, Journal of the
Electrochemical Society, 160 (8), 2013, pp B132-137.
[2] J. Fevery, Liver International 28, 2008, pp 592-605.
[3] X. Wang, J. R. Chowdhury, N. R. Chowdhury, Current Paediatrics 16, 2006, pp 70-74.
181
F-1
Bipolar Electrochemistry for High-throughput Corrosion
Screening
Sara Munktell, Mats Tydén, Jonas Högström, Leif Nyholm, Fredrik Björefors
Department of Chemistry - Ångström Laboratory,
Uppsala University, Box 538, SE-75121 Uppsala, Sweden
Email: [email protected]
In this work it is demonstrated that bipolar electrochemistry can be used for high-throughput
corrosion testing, covering a wide potential range in one single experiment. This technique,
combined with rapid image analysis, constitutes a simple and convenient way to screen
corrosion behaviour of conducting materials and corrosion protective coatings1.
The bipolar effect arises when an electronic conductor is isolated in an electrolyte
and is subjected to a sufficiently high electric field. In this case an electrochemical potential
gradient is formed across the surface of the electronic conductor, which induces anodic and
cathodic reactions depending on the potential at any given point2-4. This effect is
schematically depicted in Figure 1.
Stainless steel samples (SS304), acting as bipolar electrodes, were immersed in
sulfuric or hydrochloric acid and exposed to an electric field to establish a potential gradient
along the surface of the sample. In this way, the same steel sample was exposed to a wide
range of cathodic and anodic conditions, ranging from potentials yielding hydrogen evolution
to potentials well into the trans-passive region.
This wireless approach enables rapid simultaneous comparison of numerous
samples, and also provides the opportunity to perform experiments on samples that are of a
complex shape, or which are otherwise difficult to employ in standard electrochemical
corrosion tests. An SEM image of an example of a typical pitting corrosion gradient on a
bipolar electrode of SS304 in hydrochloric acid is shown in Figure 2. The size of the pits
increases towards the left in the image, which is at the anodic end of the sample.
Acknowledgements
The authors wish to acknowledge the Swedish research council FORMAS and ÅForsk for
funding (SM), (MT) and Outokumpu, Sweden for providing the steel samples.
References
[1] S. Munktell, M. Tydén, J. Högström, L. Nyholm, F. Björefors, Electrochemistry Communications
2013, 35, 274-277.
[2] C. Ulrich, O. Andersson, L. Nyholm, F. Björefors, Angew. Chem. Int. Ed. 2008, 47, 3034-3036.
[3] G. Loget, A. Kuhn, Anal. Bioanal. Chem. 2011, 400, 1691-1704.
[4] C. Ulrich, O. Andersson, L. Nyholm, F. Björefors, Analytical Chemistry 2009, 81, 453-459.
182
F-2
Electrochemical study of the tetraferrocenyl-cavitand
Lívia Nagya, László Kollára,b, Géza Nagya,b
a.) University of Pécs, János Szentágothai Research Centre,
7624 Pécs Ifjúság útja 22.HUNGARY, [email protected]
b.) University of Pécs, Faculty of Science, General and Physical Chemistry,
7624 Pécs Ifjúság útja 6.HUNGARY
A tetraferrocenyl-cavitand was synthesized from tetraethynyl-cavitand through a fourfold
copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction, one of the most important
example of the so-called click-reactions, using ferrocenylmethyl azide as coupling partner in
65 % yield. Click-reactions, both minimizing the generation of hazardous substances and
maximizing the reaction efficiency, are excellent representatives of the “green chemistry”
approach, an important contribution to sustainable development.The electrochemical property
of the new tetraferrocenyl-cavitand molecule was investigated in dimethyl formamide solvent
using conventional and micro size platinum working electrodes. Quasi reversible redox
character was found with one oxidation and one reduction wave of diffusion character. No
electrode fouling could be observed.
Different methods were used for determination of the diffusion coefficient of this species. In
part of the measurements chronoamperometric measurements with microelectrode were
carried out and evaluated according to the method introduced by Oki and Osteryoung.
Amperometric measurements with microelectrodes, as well as CV-s with conventional size
electrode were also used in these studies.
The number of electrons taking part in the redox process was also determined using different
methods. Based on that number it could be decided how many of the four electroactive
groups are active in the electrode reactions. Measurements were carried out with different
ferrocene derivatives, using the same cells, electrodes and conditions. The obtained results
were compared with the behavior of the new cavitand. The adsorption character of the
cavitand and its electrocatalytic character were also checked.
Acknowledgement
The authors, appreciate the support of the foundations New Széchenyi Plan, SROP-4.2.2.A11/1/KONV-2012-0065, Synthesis of supramolecular systems, examination of their
physicochemical properties and their utilization for separation and sensor chemistry
183
F-3
Design and Assembly of pH-Sensitive Lipidic Cubic Phase
Matrices for Drug Release
Ewa Nazaruka, Monika Szlęzaka, Ehud Landaub, Renata Bilewicza
a
Faculty of Chemistry, University of Warsaw,
Pasteura 1, 02-093, Warsaw, Poland
b
Department of Chemistry, University of Zurich, Winterthurerstrasse 190,
CH-8057 Zurich, Switzerland
[email protected]
Bicontinuous lipidic cubic phases (LCPs) exhibit a combination of material properties that
make them highly interesting for various biomaterial applications: they are non-toxic,
biodegradable, optically transparent, thermodynamically stable in excess water, and can
incorporate active molecules of virtually any polarity. An interesting property of cubic phase
is also their ability to disperse into nanoparticles called “cubosomes”. Cubosomes are less
viscous and they can stably exist in equilibrium with aqueous solution and retain an internal
bicontinuous structure unchanged. The structure and dynamics of lipidic mesophases, and
their interactions with guest molecules can be tailored by applying additives, thereby
achieving novel materials with improved functions for drug delivery. [1, 2]
Here we present a molecular system comprising host lipid, water, and designed lipidic
additive, which form a structured, pH-sensitive lipidic matrix for hydrophilic as well as
hydrophobic drug incorporation and release. pH-sensitive LCP was developed with the use of
newly synthesized lipids. Tunable interactions with the lipidic matrix led to the observed pHdependent kinetics of drug release from the phase. pH sensitive cubic phase was developed
with the use of newly synthesized lipids: diacidic lipid with carboxylic group and a basic lipid
that contains an amine group. A small amount of such lipidic additive added to the monoolein
LCP modified the release rate of the drug.
Doxorubicin, a model drug that contains an amine group and a hydrophobic part, was loaded
into the cubic phase and cubosomes. The particle size, zeta potential of the cubosomes were
determined with the use of dynamic light scattering. The inner cubic structure of the prepared
materials was confirmed by SAXS. In vitro pH-sensitive doxorubicin release profile was
determined with the use of electrochemical methods. The complex interactions with the cubic
phase lead to the observed pH - dependent removal of the drug from the phase. The release
rate of loaded DOX was slow at pH 7.4 but increased significantly at acidic pH either for LCP
or cubosomes. Protonated doxorubicin which carries a positive charge is soluble in water,
whereas unprotonated one is insoluble in aqueous solution and prefers hydrophobic lipidic
environment. At pH 5.8 protonated doxorubicin resides mainly in the aqueous channels,
where diffusion is faster, whereas unprotonated form is embedded in the lipidic bilayer and
less prone to leaching from this environment to the solution. The pH dependence of the rate of
doxorubicin removal from the cubic phase may be exploited in the drug release into tumour
cells whose pH is lower than that of the normal cells.
[1] E. Nazaruk, M. Szlęzak, E. Górecka, R. Bilewicz, Y. M. Osornio, P. Uebelhart, E. M. Landau,
Langmuir, 2014, 30 (5), pp 1383–1390,
[2] E. Nazaruk, E. Górecka, R. Bilewicz, Journal of Colloid and Interface Science, 2012, 385(1), pp 130-136.
184
F-4
Electrochemical immunoassay based on a 96-well screen-printed
ELISA plate for cardiac troponin detection
M.M.P.S. Neves, P. Fanjul-Bolado, D. Hernández-Santos
DropSens, S.L., Edificio CEEI, Parque Tecnológico de Asturias, 33428 Llanera, Asturias, Spain
([email protected])
Acute myocardial infarction, commonly known as a heart attack, is the principal cause of
adult mortality and morbidity in the western world and, consequently, places a massive
burden on healthcare services and the economy [1]. A multiplexed point-of-care utility that
allow health professionals to perform a fast and specific diagnostic is therefore of the utmost
importance. Currently, cardiac troponins (cTnT and cTnI isoforms) are recognized as the gold
standard biomarkers for the detection of myocardial damage [2].
In this work, a novel electrochemical based-immunoassay for the specific detection of cTnT,
employing a 96-well screen-printed microplate as the transducer surface, was developed. The
capture element of the proposed sandwich immunoassay was efficiently immobilized onto the
surface of the 96-well array and different concentrations of cTnT, within a range of clinical
interest, were assayed. The detection of the analyte of interest was accomplished by using
alkaline phosphatase (AP) as the enzymatic label. The analytical signal was obtained by using
two AP enzymatic substrates: 3-indoxyl phosphate/silver ions (3-IP/Ag+) [3] and the new
hydroquinone diphosphate/silver ions (HQDP/Ag+), which results were compared, namely in
terms of sensitivity. In both cases, a biometallization process, where the enzymatic reaction
gives rise to a compound that reduces silver ions in solution into a metallic deposit, took
place. Thus, the silver enzymatically deposited on the electrode surface was detected through
the oxidation peak of the silver when an anodic stripping scan was carried out. Moreover,
different methodologies for the modification, in a reproducible manner, of this 96-well
screen-printed electrochemical array, were studied. Therefore, the ELISA plate surface was
modified with carbon nanotubes (CNTs), gold nanoparticles (GNPs) and with a hybrid
combination of these carbon-gold nanomaterials (CNTs-GNPs). The reproducibility, stability
and biofuncionality of these nanostructed transducer surfaces were also studied.
The electrochemical behaviour of this immunosensor was carefully evaluated assessing
aspects as sensitivity, non-specific binding, limits of detection and reproducibility and the
analytical figures of merit were obtained.
References
[1] K. Thygesen, J.S. Alpert, H.D. White, Circulation 2007, 116, 2634.
[2] D.A. Morrow, C.P. Cannon, R.L. Jesse, L.K. Newby, J. Ravkilde, A.B. Storrow, A.H.B.
Wu, R.H. Christenson, Circulation 2007, 115, e356.
[3] P. Fanjul-Bolado, D. Hernández-Santos, M.B. González-García, A. Costa-García, Anal.
Chem. 2007, 79, 5272.
Acknowledgments
This work has been supported by the Development Agency of the Principality of
Asturias (IDEPA) through the MANUNET (ERA-NET) with the project Printed
Electrochemical Elisa and with a Jovellanos grant (ITE13-006) attributed to M.M.P.S. Neves
by the Foundation for the promotion of Applied Scientific Research and Technology in
Asturias (FICYT).
185
F-5
Electrochemical immunosensor for Ara h 1
(a major peanut allergen) detection
Rita C. Alves1,2, Filipa Pimentel2, Henri P.A. Nouws1, Raquel C.B. Marques1, M. Begoña
González-García1, M. Beatriz P.P. Oliveira2, Cristina Delerue-Matos1
1
REQUIMTE, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Rua Dr. António
Bernardino de Almeida 431, 4200-072 Porto, Portugal
2
REQUIMTE/Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua de
Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
Food allergies are a main food safety concern in industrialized countries, affecting up to 10%
of the general population. This type of adverse reaction arises mainly from an immunological
hypersensitivity mediated by allergen-specific immunoglobulin E, usually against certain food
proteins (antigens). Clinical manifestations include digestive disorders, asthma, urticaria,
atopic dermatitis, and, in some cases, life-threatening reactions as anaphylactic shock. Very
small amounts of allergens (from less than 1 mg to some grams) can cause an allergic reaction
in a sensitized individual. Therefore, in order to alert and protect allergic consumers from
allergens exposure, reliable, accurate, and highly sensitive and selective methods are
necessary [1,2]. In this work, an electrochemical immunosensor for Ara h 1 (a major peanut
allergen) detection was developed. Gold nanoparticles were electrochemically deposited on
the surface of screen-printed carbon electrodes [3]. Monoclonal mouse IgG antibodies against
a specific epitope of the Ara h 1 protein were immobilized on the electrode's surface. A
second monoclonal mouse antibody bound to alkaline phosphatase (AP) through a biotinstreptavidin interaction was used as detection antibody. AP catalyzed the dephosphorylation
of 3-indoxyl phosphate producing a compound able to reduce silver ions in solution into a
metallic deposit [4]. The deposited silver was electrochemically stripped into solution and
measured by linear sweep voltammetry. Based on the validation parameters, the developed
immunosensor showed to be precise and accurate, being able to detect very small amounts of
Ara h 1 (25 ng/ml).
Acknowledgments
Rita C. Alves is grateful to Fundação para a Ciência e a Tecnologia (FCT) for a postdoctoral research grant (SFRH/BPD/68883/2010), financed by POPH-QREN-Tipologia 4.1Formação Avançada, subsidized by Fundo Social Europeu and Ministério da Ciência,
Tecnologia e Ensino Superior. This work received financial support from the European Union
(FEDER funds through COMPETE) and National Funds (FCT) through project PestC/EQB/LA0006/2013. The work also received financial support from the European Union
(FEDER funds) under the framework of QREN through Project NORTE-07-0124-FEDER000069. The authors are greatly indebted to all financing sources.
References
[1] Berin, M.C., Sicherer, S., 2011. Curr. Opin. Immunol. 23, 794-800.
[2] Alves, R.C., Barroso, M.F., González-García, M.B., Oliveira, M.B.P.P., Delerue-Matos,
C., 2014. Crit. Rev. Food Sci. Nutr., in press
[3] Martínez-Paredes, G., González-García, M.B., Costa-García, A., 2009. Electrochim. Acta
54, 4801-4808.
[4] Fanjul-Bolado, P., Hernández-Santos, D., González-García, M.B., Costa-García, A., 2007.
Anal. Chem. 79, 5272-5277.
186
F-6
Multiplexed electrochemical immunosensor for detection of breast
cancer markers
Raquel C.B. Marques1, Estefanía C. Rama2, Subramanian Viswanathan3, Henri P.A. Nouws1,
Cristina Delerue-Matos1, M. Begoña González-García1
1
REQUIMTE, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Rua Dr. António
Bernardino de Almeida 431, 4200-072 Porto, Portugal ([email protected]).
Departamento de Química Física y Analítica, Universidad de Oviedo, Av. Julián Clavería 8, 33006 Oviedo,
Spain
3
Department of Industrial Chemistry, Alagappa University, Karaikudi-630003, Tamilnadu, India.
2
The majority of breast cancer diagnostics in developed countries is carried out by
mammographic screening programs. However, mammography screening has moderate
sensitivity and specificity and a low positive-predictive value in younger women. Therefore,
research has been conducted to identify the critical biochemical changes in cancer and has led
to advances in its detection and treatment [1]. The detection of tumor markers has a major
importance for the diagnosis of the onset of breast cancer [2] and treatment. The established
circulating biomarkers include cancer antigen 15-3 (CA 15-3) and the extracellular domain of
the human epidermal growth factor receptor 2 (HER2 ECD) [3,4]. In this work a multiplexed
electrochemical immunosensor for the detection of CA 15-3 and HER2 ECD was developed.
This sensor was fabricated on a dual screen-printed carbon electrode, with two working
electrodes, which were nanostructured with gold nanoparticles. The biosensing phase of the
immunosensor was constructed by immobilization (adsorption) of monoclonal (capture) antihuman CA 15-3 and HER2 ECD antibodies on the transducer surfaces, followed by surface
blocking with casein. After the incubation with the antigens (CA 15-3 and HER2 ECD) and
monoclonal biotin conjugated (detection) anti-human CA 15-3 and HER2 ECD antibodies,
alkaline phosphatase linked to streptavidin (S-AP) was added. Then the enzymatic substrate
(a mixture of 3-indoxyl phosphate and silver ions) was placed on the sensor and the analytical
signal was obtained through the anodic stripping of the enzymatically generated metallic
silver by linear sweep voltammetry [5]. The developed immunosensor could be useful in the
diagnostic and follow-up of breast cancer patients. However, additional studies using serum
samples from healthy individuals and cancer patients should be conducted to evaluate the
sensor's utility and validate its performance in clinical settings.
Acknowledgments
This work received financial support from the European Union (FEDER funds through
COMPETE) and National Funds (FCT, Fundação para a Ciência e a Tecnologia) through
projects PTDC/SAU-ENB/114786/2009 and Pest-C/EQB/LA0006/2013. Estefanía Costa
Rama thanks the Government of Principado de Asturias for the award of a Severo Ochoa
predoctoral grant (BP11-097). The authors are greatly indebted to all financing sources.
References
[1] Cole, K.D., He, H.-J., Wang, L., 2013. Proteomics Clin. Appl. 7, 17-29.
[2] Levenson, V.V., 2007. Biochim. Biophys. Acta 1770, 847-856.
[3] Nicolini, A., Carpi, A., Tarro, G., 2006. Front. Biosci. 11, 1818-1843.
[4] Tsé, C., Gauchez, A.-S., Jacot, W., Lamy, P.-J., 2012. Cancer Treat. Rev. 38, 133-142.
[5] Fanjul-Bolado, P., Hernández-Santos, D., González-García, M.B., Costa-García, A., 2007.
Anal. Chem. 79, 5272-5277.
187
F-7
Application of Silver Solid Amalgam Electrode for Determination
of 5-Nitroindazole
K. Nováková1,2*, T. Navrátil1, V. Hrdlička3, J. Barek3 and J. Chýlková2
1
J. Heyrovský Institute of Physical Chemistry of the AS CR, v.v.i., Dolejškova 3, 182 23 Prague 8, Czech
Republic ([email protected])
2
University of Pardubice, Faculty of Chemical Technology, Institute of Environmental and Chemical
Engineering, Studentská 573, 532 10 Pardubice, Czech Republic
3
Charles University in Prague, Faculty of Science, Department of Analytical Chemistry, UNESCO Laboratory
of Environmental Electrochemistry, Albertov 6, 128 43 Prague 2, Czech Republic
*[email protected]
Electrochemistry has been utilized for investigations of nitro-group containing compounds for
a long time [1, 2]. It is based on reduction of the nitro group at the aromatic or heterocyclic
ring [3]. 5-Nitroindazole was chosen as a representative compound from the wide group of
nitrated polycyclic aromatic hydrocarbons [4].
The voltammetric behaviour of 5-nitroindazole (5-NI) was studied by differential pulse
voltammetry (DPV) and cyclic voltammetry (CV) at polished (p-AgSAE) and mercury
meniscus modified (m-AgSAE) silver solid amalgam electrodes (inner diameter 0.5 mm). The
optimum conditions for DPV determination of 5-NI were found in Britton-Robinson buffer.
The reaction mechanism was investigated using CV and elimination voltammetry with linear
scan (EVLS). DPV with optimized parameters was used for determination of 5-NI in analysed
solutions. The limits of detection were calculated as 0.14 Pmol L-1 for m-AgSAE and
0.47 Pmol L-1 for p-AgSAE.
Structure of 5-nitroindazole
Acknowledgments
K. Nováková thanks for the support of University of Pardubice (grant No.
SGSFCHT/2014006), and T. Navrátil thanks for the support of the Czech Science Foundation
(project GA ČR No. P208/12/1645).
References
[1] S. Sebkova, T. Navratil, M. Kopanica, Chem. Listy 2003, 97, 843.
[2] J. Fischer, L. Vanourkova, A. Danhel, V. Vyskocil, K. Cizek, J. Barek, K. Peckova, B.
Yosypchuk, T. Navratil, Int. J. Electrochem. Sci. 2007, 2, 226.
[3] K. Peckova, J. Barek, T. Navratil, B. Yosypchuk, J. Zima, Anal. Lett. 2009, 42, 2339.
[4] C. Olea-Azar, H. Cerecetto, A. Gerpe, M. Gonzalez, V. J. Aran, C. Rigol, L. Opazo,
Spectrochimica Acta Part a-Molecular and Biomolecular Spectroscopy 2006, 63, 36.
188
F-8
Behavior of Thiosulfate Anions on Charged Surfaces and Some
Similarities with the Agglomeration of Silver (Nano)Particles.
Ladislav Novotný
University Pardubice, Faculty of Chemical Technology, Institute of Environmental and Chemical Engineering,
Studentska 573, 532 10 Pardubice, Czech Republic ([email protected])
The study of interactions of thiosulfate ions on charged surfaces is usually associated with
their voltammetric determination on the surface of polarized electrodes. So far being limited
to proving the conditions of adsorption or another accumulation of S2O32- on the surface of
the electrode, which could be utilized for example for their determination using the method of
"cathodic stripping voltammetry" CSV. This is the case, for example in the initiated
electrosorption of S2O32- and the formation of products Hg2+ with S2O32- at a surface of a
mercury electrode [1], which may result, by application of a cathodic potential scan, to a
reduction of Hg2+ to Hg and therefore to an usable analytical CSV-signal for determination of
concentration S2O32-. Direct indicative electrocapillary measurements [2] proved an
adsorption S2O32- at potentials more positive than about -0.35 V (vs. SCE). However, the
evaluation of parameters by conventional procedures led to certain inconsistency between the
resulting data. Examples include deviations in the position of potential E´max of the maximum
value of the adsorption coefficient (β)m (evaluated, e.g., from the Langmuir isotherm (βL)m and
from the Frumkin isotherm (βF)m) in comparison with the measured potential of maximum
adsorption Emax.
More accurate measurements and theoretical considerations [3] led to derivations and models,
which captured much better the complex of present interactions between the particle and the
charged interface and also various present particles between themselves, incl. the formation of
possible agglomerates of nano dimensions. Series equations [3], e.g., of the type like f1(Y)˜
exp f2(Y) = k(X) or k(X,Y), respectively even more complex terms in the just mentioned or
logarithmic form were suggested and used, which were better able to reflect the physicochemical nature of the described events (although some in a limited scope of changes X). X
and Y in this case denote the corresponding independent and dependent variables, their
changes, relative modifications or dimensionless quantities.
The results of the mentioned evaluation removed the aforementioned inconsistency in values
(β)m and provided a better understanding of present interparticle interactions. They also led to
an attempt of a similar method of data analysis, for example in the case of time-dependent
agglomeration of silver or other similar (nano)particles in a solution where physically
analogous processes can play a role, as well. From the measured [4] dependence of the
hydrodynamic diameter (DH) of silver nanoparticles (nAg) on the time t, in a diluted solution,
there was thus possible, for instance, due to calculation (by extrapolation) to estimate the
approximate size of the initial nucleus at time t o 0 about 30 - 40 nm.
The work has been supported by MSM 0021627502.
References
[1]
[2]
[3]
[4]
I. Ciglenecki, B. Cosovic, Electroanalysis 1997, 9, 775.
J. Krista, M. Kopanica, L. Novotny, Anal. Chim. Acta 1999, 386, 221.
L. Novotny: DrSc.-Thesis. Acad. Sci. of the Czech Republic, Prague, 1998.
J. Oprsal, P. Knotek, M. Pouzar, J. Palarcik, L. Novotny, Chem. Listy 2013, 107, 386.
189
F-9
Construction of three-dimensional DNA hydrogels from linear
building blocks
Tanja Nöll, Holger Schönherr, Daniel Wesner, Michael Schopferer, Thomas Paululat,, Gilbert
Nöll*
Nöll Junior Research Group, Organic Chemistry, Chem. Biol. Dept., Faculty IV, Siegen University, AdolfReichwein-Str. 2, 57068 Siegen, Germany
*Nöll Junior Research Group, Organic Chemistry, Chem. Biol. Dept., Faculty IV, Siegen University, AdolfReichwein-Str. 2, 57068 Siegen, Germany, [email protected]
In this study a three-dimensional DNA hydrogel was generated from short linear double
stranded DNA (dsDNA) building blocks. The dsDNA building blocks were equipped with
sticky ends, i.e. they comprised two complementary overhangs of single stranded DNA
(ssDNA), which allowed further self-assembly. The length of the resulting supramolecular
dsDNA structures varies with temperature and the generated hydrogel is thermoresponsive.
For T Œ 60 °C the average diffusion coefficients of the supramolecular dsDNA structures
formed by self-assembly were determined by Diffusion Ordered NMR spectroscopy (DOSYNMR) and the hydrogel was also characterized by temperature-dependent rheological
measurements. Below the gel point, which was found to be at 42 ± 1 °C, the resulting material
behaved as a true gel of high viscosity with values for the storage modulus G' being
significantly larger than that for the loss modulus G''. Frequency-dependent rheological
measurements of the gel at 20 °C revealed a mesh size [ of 15 nm. AFM analysis of the
diluted hydrogel in the dry state showed densely packed structures of entangled chains, which
are expected to contain also multiple interlocked rings, catenanes, etc..
The high viscosity of the DNA hydrogel built from linear building blocks can be attributed to
the flexibility of the involved dsDNA. Currently the diffusion of small molecules (such as
13
C-labeled sucrose) inside the hydrogel is under investigation using DOSY-NMR. Due to its
interesting material properties this new type of hydrogel is of strong interest for applications
in drug delivery or biosensor development.
190
F-10
Monitoring DNA hybridization by surface plasmon resonance
(SPR), quartz crystal microbalance (QCM) measurements, and
electrochemical impedance spectroscopy (EIS)
Gilbert Nöll*, Stephan Vogt, Qiang Su , Cristina Gutiérrez-Sánchez
*Nöll Junior Research Group, Organic Chemistry, Chem. Biol. Dept., Faculty IV, Siegen University, AdolfReichwein-Str. 2, 57068 Siegen, Germany, [email protected]
In this study the three different experimental techniques surface plasmon resonance (SPR),
quartz crystal microbalance with dissipation mode (QCM-D) measurements, and
electrochemical/faradaic impedance spectroscopy (EIS) using the ferri/ferrocyanide couple as
redox probe were evaluated with respect to their ability to monitor DNA hybridization events.
The hybridization of ssDNA (20 bases, target) at a gold sensor surface equipped with
complementary thiol-modified ssDNA (20 bases, capture probe) was examined.
SPR and QCM-D turned out to be reliable experimental techniques, which could be used to
follow the adsorption/hybridization kinetics as well as to estimate the amount of adsorbed
DNA. During the QCM-D measurements also solvent molecules trapped in the DNA
monolayer contributed to the determined surface bound mass. While during rinsing with
buffer the vast majority of the target DNA stayed captured, rinsing the sensor surface with
pure water resulted in quantitative dehybridization. The sensor surfaces could be used to
monitor several hybridization/dehybridization steps by SPR or QCM-D measurements
without significant decrease in performance.
In contrast, EIS using the ferri/ferrocyanide redox couple did not provide consistent results.
Combined EIS and SPR or QCM-D measurements revealed that during EIS the gold surface
is seriously damaged/etched due to the presence of CN-, which is released from the
ferri/ferrocyanide redox probe.
191
F-11
Electrochemical immunosensor for the determination of
interleukin-6 using poly-HRP streptavidin conjugates as labels for
signal amplification
I. Ojeda Fernández, M. Moreno-Guzmán, A. González-Cortés, P. Yáñez-Sedeño*, J.M.
Pingarrón
Department of Analytical Chemistry, Faculty of Chemistry, University Complutense of Madrid, Ciudad
Universitaria s/n, 28040-Madrid, Spain
[email protected]; *[email protected]
Interleukin-6 (IL-6) is a pleiotropic cytokine that has a critical role in the inflammatory
response, being implicated in the pathogenesis of a number of inflammatory conditions, such
as psoriasis, rheumatoid arthritis, cardiovascular disease, and inflammatory bowel disease. In
addition, IL-6 has been identified as an important cancer biomarker. In healthy individuals,
IL-6 is present at very low concentrations, around 6 pg/mL in serum and 15 pg/mL in saliva
and urine, while increased IL-6 levels is closely associated with mortality [1-4]. Therefore,
the determination of IL-6 levels is a useful early diagnostic tool for several diseases.
This work describes a novel immunosensor design for the determination of IL-6 involving the
covalent immobilization of anti-IL-6 antibodies onto carboxyl-functionalized magnetic
microparticles followed by the establishment of a sandwich-type immunoassay with signal
amplification using poly-HRP-streptavidin conjugates. Amperometric measurements were
performed at – 0.05 V using H2O2 as enzyme substrate and HQ as electron mediator. This
simple and relatively low cost immunosensor configuration allowed to develop a method for
the determination of IL-6 in a linear range of concentrations between 1.75 and 500 pg/mL and
a limit of detection of 0.39 pg/mL. A good storage stability for the anti-IL-6-MBs
immunoconjugate was found, the amperometric current being practically constant for at least
22 days. Moreover, no significant cross-reactivity was observed from other potentially
interfering substances such as IL-8, IgG, prolactin and cortisol, at the concentrations usually
found in saliva, as well as from creatinine and uric acid at the levels to be expected in urine.
The developed immunosensor was applied with good results to the determination of IL-6 in
spiked urine samples and saliva.
[1] G.A. Messina, N. V. Panini, N.A. Martínez, J. Raba, Anal. Biochem., 380 (2008) 262
[2] T. Yang, S. Wang, H. Jin, W. Bao, S. Huang, J. Wang, Sens. Actuat.B 178 (2013) 310
[3] L.M. Rodríguez, B. Robles, J.M. Marugán, A. Suárez, F. Santos Pediatr. Nephrol.
23(2008) 429
[4] J.L. Ebersola, J.L. Schuster, J. Stevens, D. Dawson III, R. Kryscio, Y. Lin, M.V. Thomas,
C.S. Miller, J. Clin. Immunol. 33 (2013) 271
192
F-12
Electrochemical detection of free cholesterol using potassium
thiocyanate and nickel (II) and cobalt (II) chlorides as
electrocatalysts
Andrey Okhokhonin, Alisa Kozitsina, Anatoly Matern
Ural Federal University, Institute of Chemistry and Technology, Ekaterinburg, Russia ([email protected])
The level of cholesterol in human blood and tissues is one of the most important
characteristics in monitoring of health state, because it has direct link to progress of
atherosclerotic disorders in human body. Regulation and permanent monitoring the
cholesterol level in blood require development of new express selective sensitive and cheap
methods of determination of its concentration. Traditional enzymatic and colorimetric
methods, which are widely used for cholesterol detection, aren’t available to use ubiquitously
because of imprecision of analyzed solution color interpretation, high costs of enzymes and
their poor stability due to different physical and chemical influences like temperature and pH.
Thus actual problem is development of new non-enzymatic and sensitive cholesterol detection
method which is devoid of traditional methods drawbacks.
Cholesterol is oxidized in area of high potentials because it is a non-electroactive
material, that’s why perspective way of its electrochemical detection is application of
electrocatalysis. Electrocatalysis means increasing of electrochemical reaction rate and
decreasing of applying potential due to using additional substance – electrocatalyst. Such
substance acts as electron mediator.
The aim of this work is development of new enzyme-free electrochemical method of
detection of free cholesterol concentration using potassium thiocyanate and nickel (II) and
cobalt (II) chlorides as electrocatalysts.
Assay consists of the following steps. A certain amount of catalyst is dissolved in 10 ml
of N,N-dimethyl-formamide (DMF) containing 0.1M tetrabutylammonium tetrafluoroborate
(TBABF4) as indifferent electrolyte and cyclic voltammogram or chronoamperogram are
registered. Then cholesterol as analyte is added to the solution dropwise in the form of 0.1M
solution in DMF with stirring and cyclic voltammogram or chronoamperogram are registered
again. The difference between oxidation currents indicates amount of added cholesterol.
It has been found that cholesterol addition to solution leads to increasing of anodic
current in the presence of one of three considered catalysts, meanwhile in absence of
electrocatalysts no any changes are registered with cholesterol additions. Moreover, the
amperometric current followed Michaelis-Menten’s enzymatic model for cholesterol
concentrations in the range of 50 μM to 2.5 mM. Calibration curve obtained by amperometric
method shows linear relationship between the current and the cholesterol concentration.
The mechanism of the electrocatalytic oxidation of cholesterol was suggested, kinetic
parameters of the reaction was determined, and analytical characteristics of developed method
of cholesterol concentration determination were calculated.
193
F-13
Electrochemical characterization of Bi sputtered screen printed
electrode (BispSPE)
M.R. Palomo Marín, E. Bernalte Morgado, E. Pinilla Gil*
[email protected]
*Department of Analytical Chemistry, University of Extremadura, Av. de Elvas, s/n E-06006, Badajoz, Spain
Screen printed electrodes are routinely used as electrochemical sensors for the determination
of metal ions in industrial, biomedical and environmental applications because their low cost,
miniaturized size and connectivity with portable instruments for field determination of
analytes [1]. Specifically, Bi-modified screen printed electrodes (BiSPE) have become an
"environmental friendly" alternative to mercury electrodes for ASV of trace levels of several
metals like Zn(II), Cd(II) and Pb(II). Regarding the working electrode Bi-coating method,
three general procedures are well-established: (i) in-situ plating method, where Bi(III) ions are
added to the sample solution and electrochemically codeposited on the electrode surface
during the analysis, (ii) ex-situ plating method, where the SPE is immersed into a Bi(III)
solution for electroplating as metallic Bi on the electrode surface before use, and (iii) "bulk"
method, where the modification takes place during the SPE production by mixing the graphite
ink with a given amount of a Bi precursor before the printing procedure. The Bi precursor is
electrochemically reduced at a selected potential to metallic Bi just before use [2]. An
alternative and more recent fabrication method is based on bismuth sputtering on a silicon or
ceramic substrate leading to a thick Bi film working electrode [3, 4]. This approach simplifies
the fabrication process since neither the Bi(III) plating solution nor a conductive substrate is
required [3]. Scarce analytical applications of Bi sputtered screen printed electrodes (BispSPE)
have been described in the literature [1, 3, 4].
In this work, commercially available BispSPEs have been characterized by cyclic voltammetry
and electrochemical impedance spectroscopy (EIS). Additionally the BispSPE surface was
also characterized by scanning electron microscopy (SEM) and X-ray photoelectron
spectroscopy (XPS). The reproducibility and stability of the electrode response for Zn(II),
Cd(II) and Pb(II) have been also explored. This study has provided useful information for a
better understanding of BispSPE behaviour in electroanalytical applications, particularly in
the anodic stripping voltammetry of Zn(II), Cd(II) and Pb(II).
[1] Meng Li, Yuan-Ting Li, Da-Wei Li, Yi-Tao LongǡƒŽ›–‹…ƒŠ‹‹…ƒ…–ƒ͹͵ͶሺʹͲͳʹሻ
͵ͳȂͶͶ
[2] Núria Serrano, Arístides Alberich, José Manuel Díaz Cruz, Cristina Ariño, Miquel
Esteban, Trends in Analytical Chemistry 46 (2013) 15-29
[3] Velia Sosa, Nuria Serrano, Cristina Ariño, José Manuel Díaz Cruz, Miquel Esteban,
Talanta 119 (2014) 348-352
[4] Preetha Jothimuthu, Robert A. Wilson, Josi Herren, Xing Pei, Wenjing Kang, Rodney
Daniels, Hector Wong, Fred Beyette, William R. Heineman, Ian Papautsky. Electroanalysis
2013, 25, No. 2, 401 – 407
Acknowledgments: this work is supported by the Spanish Ministry of Science and Innovation
(project CTQ2011-25388), Gobierno de Extremadura (GR10091), and the European Union
(FEDER).
194
F-14
Hybrid electric power devices
for simultaneous generation and storage of electric energy
Dmitry Pankratova,b*, Zoltan Bluma, and Sergey Shleeva,b
b
a
Biomedical Sciences, Health & Society, Malmö University, 205 06 Malmö, Sweden
NBICS Center, National Research Centre "Kurchatov Institute", 123 182 Moscow, Russia
[email protected]
Here we show a new kind of device, namely a self-charging supercapacitor (SCSC) or, in
other words, a charge-storing fuel cell. A SCSC is a combination of an electrochemical
capacitor and a fuel cell in a singular indivisible module. To create efficient devices, which
can be miniaturised down to the nm scale even, and used for short-time high-current and longtime low-current practical applications, both elements (capacitive and electrocatalytic) were
built from nano(bio)composite materials. The energy storing parts were built from a
conducting organic polymer (e.g. polyaniline (PANI) and polypyrrole (PPy))/carbon
nanotubes (CNT) nanocomposites immobilised on the surface of gold or graphite electrodes.
The energy generating parts of SCSCs were based on non-biological organic (PANI) or
inorganic (platinum) or biological (redox enzymes) catalysts, as schematically presented
below.
Schematic representations of self-charging electrochemical (bio)capacitor.
(Left) self-charging biosupercapacior, (Right) self-charging electrochemical capacitor.
Operating in a pulsed power mode, SCSCs based on biological and non-biological catalysts
provided a maximum power density of 1.2 mW cm-2 and 1.4 mW cm-2 at 0.38 V, respectively.
Thus, the power output was improved by a factor of about 170 in comparison to fuel cells
based on the same catalysts.
References:
1. Pankratov, D.; Blum, Z; Suyatin, D. B.; Popov, V. O.; Shleev, S. Self-charging
electrochemical biocapacitor. ChemElectroChem, 2014, 2(1), 343-346.
2. Pankratov, D.; Falkman, P.; Blum, Z.; Shleev, S. A hybrid electric power device for
simultaneous generation and storage of electric energy. Energy and Environmental Science,
2014, 7(3), 989-993.
The work has been supported financially by the Swedish Research Council (2013-6006) and
by the Russian Foundation for Basic Research (13-04-12083 ofi_m).
195
F-15
Nano-immunoassay onto a screen printed electrode for HER2
breast cancer biomarker determination
Stéphanie Patris, Pieter De Pauw*, Marie Vandeput, Serge Muyldermans* and Jean-Michel
Kauffmann.
Laboratory of Instrumental Analysis and Bioelectrochemistry, Faculty of Pharmacy, Université Libre de
Bruxelles, Boulevard du Triomphe, Campus Plaine, CP 205/06, 1050, Brussels, Belgium ([email protected])
* Laboratory of Cellular and Molecular Immunology, Faculty of Sciences, Vrije Universiteit Brussel, Pleinlaan
2, Campus Oefenplein, gebouw E, verd. 8 , 1050 Brussels, Belgium
The present project aimed at developing a point of care diagnostic device for HER2
determination in serum. HER2 is a transmembrane glycoprotein, member of the epidermal
growth factor receptor family. The HER2 activation promotes cell proliferation and opposes
apoptosis. An excess of HER2 due to a gene mutation has been shown to play an important
role in certain aggressive types of breast cancer, increasing the risk to develop metastases and
a worse response to both chemotherapy and hormonal therapy. HER2 is quantified as an
important biomarker and is a target of therapy for the disease [1, 2]. The innovation consisted
in applying nanobodies (Nanobody®) onto a carbon based screen printed electrode (SPE) for
electrochemical immunosensing. Nanobodies are the smallest (15 kDa) intact antigen binding
fragments that can be derived from a functional heavy chain-only antibody. The first
nanobody was generated from camel single domain antibodies. Nanobodies have similar
antigen binding properties compared to whole antibodies, they are readily produced by E. coli
and are resistant to heat and reducing agents. Their small size allows an efficient access to
their target and permits to create nano-immunosensors with low surface blocking [3, 4]. The
nano-immunoassay developed in the present work was of sandwich-type format with the
capture anti-HER2 nanobody covalently immobilized onto the SPE. The detection nanobody,
raised against another epitope of HER2, was labeled with horseradish peroxidase. The best
performing and optimized immunoassay conditions consisted of 2 minutes and 20 minutes for
the first and the second incubation times, respectively. The signal obtained was proportional
to the logarithm of HER2 concentration between 1 and 200μg/mL. The nanobody-SPE
storage stability, under dry conditions at 4°C, was of a minimum of three weeks.
References:
1. J. W. Park, R. M. Neve, J. Szollosi, C. C. Benz, Clinical Breast Cancer, 8 (5) (2008) 392401.
2. C.B. Moelans, R.A. de Weger, E. Van der Wall, P.J. van Diest, Oncology/Hematology 80
(2011) 380–392.
3. P. Chames, D. Baty, Médecine/Sciences, 25 (2009) 1159-1161.
4. S. Muyldermans, Molecular Biotechnology 74 (2001) 277-302.
196
F-16
!
"#
$%&'()&)&'&"*+*)+&,-./012-.22
0*3,4),5
#3%4',5
61)&%&7&18*&8)'&&,
+'&**8&*7*&
&*8*&*8,+*%*&9%&%&
*8&8),
:3,6;5&8'3,6-57&&%&*&&'
&& & * * &', <&* 8*& ' * ' 7 &%*)*8''&7*''&%=>/?,+*&
7&'7*)&%*91*%&&&*
&&>-?8*&9%&'>/?,6&7&&
*))9''&7,
<&* %&'& ' * &9 %&1'1& 8& 7
)%)&'9%%&&,<&*
'& &% 7 % &%*) *) ' * %&)
8&, * '' ' * &9 & 8) 7 8 %& ,
'&
>/?,,
@,
"<&*,8,
>-? , A, A& @, , , "
*B-C3-2/.5-;D,
7)
*&&*'8*<&%+:&*A8A&E&"&B
(,
"/1.,/1@EE12F1G12/1/-C,
197
F-17
Novel electrochemical platforms for cardiovascular diseases
diagnosis
M. Pedreroa, B. Esteban-Fernández de Ávilaa, S. Campuzanoa, V. Escamilla-Gómeza, J.-P.
Salvadorb,c, M.-P. Marcob,c and J. M. Pingarróna
a
Departamento de Química Analítica, Facultad de CC. Químicas, Universidad Complutense de Madrid,
E-28040 Madrid, Spain. ([email protected]).
Nanobiotechnoly for Diagnostics (Nb4D), Biomateriales y Nanomedicina (CIBER-BBN), Jordi Girona 18-26,
08034 Barcelona, Spain.
c
CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Jordi Girona 18-26, 08034 Barcelona,
Spain.
b
Increasing concentrations of cardiac markers in serum are associated with recurrent
cardiovascular diseases (CVD) events and high death rates, so the development of fast and
reliable methods for the detection of these proteins can help in clinical diagnosis. In these
sense, two novel strategies for the construction of disposable amperometric immunosensors
are described. Both designs are based on sandwich formats and on the use of screen-printed
carbon electrodes (SPCEs).
In the first approach, which was applied to the determination of human C reactive protein
(CRP), an amperometric magnetoimmunosensor involving covalent immobilization of the
capture antibody (antiCRP) onto carboxylic-modified magnetic beads (HOOC-MBs) activated
with
N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide
(EDC)
and
Nhydroxysulfosuccinimide (sulfo-NHS) has been developed. After the antigen–antibody
reaction, an incubation step with a biotinylated antibody (biotin-antiCRP) and a StreptavidinHRP (Strp-HRP) commercial conjugate was employed to allow monitoring of the affinity
reaction [1].
On the other hand, a disposable integrated amperometric sandwich immunosensor for
lipoprotein(a) (Lp(a) determination is described for the first time based on the covalent
immobilization of a selective capture antibody (antiLp(a)) on the surface of N-[Nα,Nαbis(carboxymethyl)-L-lysine]-12-mercaptododecanamide (HS-NTA)-modified SPCEs, using
EDC and sulfo-NHS. After a blocking step with a 1:1 PBS diluted skimmed milk solution, the
modified antiLp(a)-SPCEs were incubated with a mixture solution containing a variable
concentration of Lp(a) and fixed concentrations of a specific biotynilated antibody (biotinantiLp(a)) and the Strp-HRP conjugate.
In both approaches the final amperometric responses were measured at 0.10 V (vs the Ag
pseudo-reference electrode), using the 3,3′,5,5′-tetramethylbenzidine (TMB)/H2O2 system.
The implemented methodologies exhibited an excellent analytical performance, achieving
LODs of 0.021 and 8 ng mL-1 for CRP and Lp(a), respectively, both well below the minimum
cut-off values commonly accepted to predict the probability of cardiovascular risk. The
immunosensors applicability was successfully demonstrated by the analysis of international
standards with certified contents and spiked serum samples.
The great analytical performance exhibited (high sensitivity and selectivity, together with low
analysis time) and the use of disposable mass-produced sensors combined with the simplicity
and easy automation and miniaturization of the required instrumentation make the developed
platforms promising, attractive and user-friendly alternative diagnosis tools for the
development of POCT devices for clinical diagnosis and prognosis through on-site
determination of these relevant biomarkers.
[1] B. Esteban-Fernández de Ávila, V. Escamilla-Gómez, S. Campuzano, M. Pedrero, J.-P. Salvador, M.-P.
Marco, J. M. Pingarrón. Sensors and Actuators B-Chem. 188 (2013) 212– 220.
198
F-18
Fitting Time-Dependence of Size of Silver Nanoparticles in
Solutions Containing Silver Ions.
Ladislav Novotný, Renáta Petráňková, Jakub Opršal, Abraham Kabutey and Miloslav Pouzar
University Pardubice, Faculty of Chemical Technology, Institute of Environmental and Chemical Engineering,
Studentska 573, 532 10 Pardubice, Czech Republic ([email protected])
Among nanomaterials, which have recently caused great interest, also belong colloidal
solutions of nanosilver. This relates in particular, first with a growing range of actual or
potential practical applications, and secondly with research into their potential , the content in
water, the ratio between the content of silver in colloidal agglomerates and soluble ion ratios
Ag+. Thanks to the antibacterial effects [1] they are used as part of disinfectants. Parallel to
this, a study of toxicity of nAg continues [2]. Up to date, no results of terrestrial studies as
well as laboratory tests of ecotoxicity were unambiguous [3, 4], because the toxicity of nAg is
obviously influenced by a wide range of factors, such as particle size, ionic composition of
the solution, pH, presence of other components of the solution, etc.. However, for example the
reaction of minor aquatic organisms for the presence of Ag indicates a considerable influence
of particle size on the harmful effects of nAg.
Among the factors of primary significance belongs consequently the evaluation of kinetic
particle growth of nAg in dependence on time, the conditions preparing the solutions, etc. The
fitting time-dependence of the hydrodynamic diameter DH of nAg-particles took place in the
range from several minutes to about 90 minutes. The objective was to determine whether and
to what extent the speed of change of DH is a function of time, or whether it is time
independent. The stock solutions of nAg of a concentration of 1 mmol˜L-1 was prepared by a
modified Tollens process [5]. The studied concentrations formed due to the dilution in ratios
from 1:4 to 1:100 with the help of medium 203 (prepared according to the OECD Guidelines).
pH values of used solutions were between 6.7 and 9.2. To verify the residual content of Ag+
in the solution or the total content of Ag the method ICP-OES was used, a mean
hydrodynamic diameter (DH) of nAg was determined on the basis of dynamic light scattering.
In selected samples, the size of the nanoparticles was displayed using AFM.
By using equations, proposed by one of the authors [6, 7], for example the type
f1(Y)˜expf2(Y)=k(X) or similar, as necessary logarithmic [incorporating relative changes
'Drel(Y) depending on the time changes 't(X)], it was found, that for example, the growth
rate of nAg in diluted solutions was constant in the range of about 10-30 minutes, and grew
after that time elapsed.
The work has been supported by MSM 0021627502 and SGSFChT_2014006.
References
[1]
[2]
[3]
[4]
[5]
[6]
[7]
S. M. Lee, K. C. Song, B. S. Lee, Korean J. Chem. Eng. 2010, 27, 688.
E. Oberdorster, Environ. Health Perspect. 2004, 112, 1058.
I. Romer, T. A. White, M. Baalousha, K. Chipman, M. R. Viant, J. R. Lead, J.
Chromatogr. 2011, A 1218, 4226.
J. Oprsal, P. Knotek, M. Pouzar, J. Palarcik, L. Novotny, Chem. Listy 2013, 107, 386.
T. M. Tolaymat, A. M. El Badawy, A. Genaidy, K. G. Scheckel, T. P. Luxton, M.
Suidan, Sci. Total Environ. 2010, 408, 999.
L. Novotny: DrSc.-Thesis. Acad. Sci. of the Czech Republic, Prague, 1998.
L. Novotny: Electroanalysis – this volume.
199
F-19
Electrochemical Determination of Coenzyme Q10 at a Glassy Carbon
Electrode
E. V. Petrova, E. I. Korotkova, O. A. Voronova, E. V. Dorozhko, A. S. Gashevskaya
[email protected]
Coenzyme Q10 is a vitamin-like soluble antioxidant found in the highest concentration in
vital organ such as the heart and pancreas. CoQ10 has been shown to be beneficial in disease
conditions ranging from Parkinson’s disease to cataracts, in addition to heart disease.
Furthermore, it is now believed that CoQ10 is the key nutrient for generating 95 percent of the
total energy required by the human body.
Quinones show a characteristic reduction and oxidation (redox) chemistry, and the
biological importance of quinines centers on the resulting electron and proton transfer functions
of these compounds. Oxidation (or reduction) of quinol (or donated to the quinine) to form a
relativity stable radical, called a semiquinone, which is resonance-stabilised. A second hydrogen
ion can be removed (or added) to complete the oxidation (or reduction) to a quinine (or quinol).
The transfer of electrons during oxidation and reduction of quinines can be used to quantity
them, using electrochemical detection.
Voltammetric experiment was carried out with a three-electrode cell in which the glassy
carbon electrode of 1 mm in diameter and silver chloride electrode were used as a working and a
counter electrode, respectively. All potential were measured and reported against the external
silver chloride reference electrode with 1M NaCl solution.
Standard solution for electrochemical experiments was prepared by dissolving a suitable
amount of coenzyme Q10 in an ethanol solution followed by heating to a temperature not more
than 35 Celsius degrees. The stock solution was stored in the dark and cool. Background solution
was prepared by dissolving standard power of Na2HPO4 in 1 L volumetric flask.
All voltammetric experiments were performed using an electrochemical analyzer “TA-2”
(“Tomanalyt” Ltd., Tomsk).
Ware obtained the influence of various conditionals (pH of background solution, scan rate,
conditioning time, conditioning potential) as a result a good and stable redox peaks of coenzyme
Q10 on a glassy carbon electrode were obtained (Figure 1).
Figure 1. Cyclic voltammogram (w=30 mV/sec, pH 6,86) without coenzyme Q10 (1) and
with 5.5∙10-6 (2), 5.5∙10-5 (3), 5.5∙10-4 (4), 5.5∙10-3 (5).
Coenzyme Q10 is electroactive at glassy carbon electrode and, therefore, a simple, rapid,
sensitive, and accurate method for compound analysis was described.
The study was supported by Grant MK-7366.2013.8 and Project on government orders to
perform works in the sphere of scientific activities of the base part of the state task Russian
Ministry of Education.
200
F-20
Electrodes modified by sulphonated Poly (Aryl Ether Sulphone)
(S-PES) for electroanalytical applications.
Valentina Pifferi, Maria Tiscar and Luigi Falciola
Università degli Studi di Milano, Department of Chemistry, ELectroANalytical Chemistry Group,
via Golgi 19, 20133, Milano, Italy ([email protected])
The use of polymeric materials for electrodes modification, with the aim of increasing the
affinity for the analyte, increasing sensitivity, lowering the limits of detection and minimizing
or completely avoiding interferences is becoming an interesting challenge in recent
electroanalytical methods. Although scarcely characterized or appropriately designed for the
modification of electrodes, thanks to its large use in fuel cell devices, Nafion® is one of the
most popular polymer also in electroanalytical applications [1].
Poly (Aryl Ether Sulphones), commonly called PES, are well-known engineered
thermoplastic materials [2], with excellent properties thanks to their aromatic skeleton and
charged groups, such as thermal and mechanical strength, resistance to oxidation and acid
catalyzed hydrolysis. Moreover, they present high glass transition temperature, good
solubility in polar aprotic and halogenated solvents, radiation stability, low flammability and
toughness, together with low costs.
In this context, sulphonated Poly (Aryl Ether Sulphone) (S-PES) was studied as a new
material for the production of modified electrodes in comparison with Nafion®.
The modified electrodes are fully characterized by cyclic voltammetry and Electrochemical
Impedance Spectroscopy (EIS).
Different parameters have been studied: the quantity and the form (acidic, salt, linear,
branched,...) of the polymer, different IECs, its method of drying, the casting solvent, its
stability in air or solution.
In particular, as the Figure shows, 1 % linear PES in the acidic form, dried at 25 °C in a oven,
after deposition from a N-Methylpyrrolidone solution, appears to present the best
performances in terms of higher voltammetric peak currents, more stability and less resistive
behaviour, superior to Nafion®, maintaining the partial electrochemical and chemical
reversibility and the diffusive control.
[1] V. Pifferi, V. Marona, M. Longhi, L. Falciola, Electrochimica Acta, 109, (2013), 447-453.
[2] R.T.S. Muthu Lakshmi, J. Meier-Haack, K. Schlenstedt, H. Komber, V. Choudhary and
I.K. Varma, Reactive and Functional Polymers, 66 (6), (2006), 634–644.
201
F-21
Characterization of Electromechanical Behavior of an
Electrochemical Cantilever System
Xueling Quan, Arto Heiskanena, Maria Tenje, Anja Boisen*
Department of Micro- and Nanotechnology, Technical University of Denmark, Lyngby, Denmark
([email protected]),
*Department of Micro- and Nanotechnology, Technical University of Denmark, Lyngby, Denmark
This work presents an investigation of the electromechanical behaviour of an electrochemical
cantilever (ECC) system, demonstrating simultaneous measurements of the surface stress and
surface energy density change at the solid-liquid interface during cyclic voltammetric
experiments. The obtained results show that the surface stress response is very sensitive to
changes in the solid-liquid interface due to e.g. the concentration of the supporting electrolyte.
Different concentrations of redox couples and various potential scan rates were applied to
characterize the surface stress change. The direction of the surface stress with respect to the
sign of the applied potential was found to be in agreement with the observations reported in
literature. For solid electrodes, the two thermodynamic quantities were shown to be
significantly different. As shown in figure 1, the change in surface stress of an Au (111)coated microcantilever was found to vary more strongly than the surface energy density in
stable electrolyte and a linear correlation between surface stress and surface charge density
was observed. These results are in an excellent agreement with previously published findings
[1, 2], and demonstrate how acquired cyclic voltammograms enable prediction of the
potential-induced surface stress profile between solid-liquid interfaces on micrometer scale.
Furthermore, these results indicate that the described ECC system is a suitable tool for
characterizing and studying the electromechanical behaviour and surface stress of solid-liquid
interfaces.
(a)
(b)
Figure1. The simultaneously determined characteristics of an Au (111)-coated electrochemical microcantilever in 200 mM
KNO3: (a) change in surface stress (red dotted curve), surface energy density (open black squares), and charge density (open
blue squares) as a function of electrode potential; (b) change in surface stress as a function of charge density change
[1] W. Haiss, et.al., Journal of Electroanalytical Chemistry, 452 (1998) 199-202.
[2] H. Ibach, Electrochimica Acta, 45 (1999) 575-581.
202
F-22
Electrochemical study of Interaction of Prebiotic peptides with Hg
Supported Phospholipid Monolayers
Ashi Rashidirst, David Bryant, Rafal Wieczorek, Terrence Kee and Andrew Nelson
School of Chemistry, University of Leeds, UK
([email protected])
Simple and small peptides offer themselves as potential candidates involved in the prebiotic
chemistry because of their presence in many meteorites [1, 2] and their role as catalytic agent
in many reactions and syntheses [3] associating the evolutionary transition from prebiotic
peptides to early proteins [3-6]. In relation to the abiogenesis theories, these simple non-living
organic precursors were built together to form more complex organic structures necessary for
commencing the establishment of simple life forms such as cell walls. Study of interactions
between short peptides and phospholipid is essential to develop an understanding about the
accumulation and partitioning of these species in the lipid matrix to form biomembranes. The
present study investigates any interactions between these simple peptides and the
phospholipid monolayer on Hg used as membrane model. Electrochemical methods have been
used to study the effect of various di- and tri-peptides on the dioleoyl phosphatidylcholine
(DOPC) monolayer assembled on Hg surface. Capacitance-potential and impedance
measurements were recorded for the DOPC monolayer on the Hg deposited on
microfabricated chip electrode in the presence of peptides under the influence of applied
electric field. Among the dipeptides, both the positively and negatively charged peptides
appeared to be more effective in interacting with DOPC monolayer as compared to the neutral
amphiphlic dipeptides. Increase in chain length in tripeptides results in substantial increase in
its effectiveness towards interacting with lipid monolayer depending upon the increase in the
hydrophobicity of the peptide. Hence, the interactions between phospholipid and peptides are
electrostatic and hydrophobic in the charged and amphiphilic peptides respectively.
This talk reports on the above findings arising from a comprehensive investigation into the
interaction of prebiotic peptides with Hg supported phospholipid monolayers under the
influence of electric field. It shows explicitly the adsorption, binding and penetration of these
species into the phospholipid membrane depending on their charge and hydrophobicity.
References
[1] K. Kvenvolden, J. Lawless, K. Pering, E. Peterson, J. Flores, C. Ponnamperuma, I.
Kaplan, C. Moore, (1970).
[2] C.P. Ivanov, R.Z. Stoyanova, I. Mancheva, Origins of life, 14 (1984) 61-68.
[3] R. Wieczorek, M. Dörr, A. Chotera, P.L. Luisi, P.A. Monnard, ChemBioChem, 14 (2013)
217-223.
[4] N. Lahav, D. White, S. Chang, Science, 201 (1978) 67-69.
[5] J.-F. Lambert, Origins of Life and Evolution of Biospheres, 38 (2008) 211-242.
[6] L. Leman, L. Orgel, M.R. Ghadiri, Science, 306 (2004) 283-286.
203
F-23
Coupling of filtrating-bulk passive sampling and SWASV on
screen printed gold electrodes for on site determination of copper
and lead in the soluble fraction of atmospheric deposition
F. Rueda-Holgado, L. Calvo-Blázquez, E. Pinilla-Gil
Department of Analytical Chemistry, University of Extremadura, Av. de Elvas, s/n E-06006, Badajoz, Spain
([email protected])
Elemental profile is a key fingerprint for the chemical characterization of atmospheric
deposition providing interesting data for the evaluation of its impact on human health and the
environment, including the assignment and apportionment of specific emission sources.
Copper and lead concentrations in atmospheric deposition are markers of traffic, oil
combustion and pigment production [1].
Field monitoring for the assessment of atmospheric deposition of selected elemental
pollutants is useful for obtaining timely estimations of emissions impacts at specific locations.
It interesting to measure not only total contents but also easily soluble elemental fractions
with enhanced bioavailability and environmental mobility. Electroanalytical strategies are
appropriate for this task by providing the needed measurement reliability with portable,
flexible, cheap, automatic and easy to use equipments. The increasing popularity of
miniaturized potentiostats and miniaturized cells, like screen printed devices, is opening new
possibilities for these applications [2].
In the present study, we have developed and optimized a voltammetric method on screen
printed gold electrodes (SPGE), for on site monitoring of Pb(II) and Cu(II) in the soluble
fraction of atmospheric deposition. Samples were collected by using a previously validated
[3] atmospheric elemental fractionation sampler (AEFS) designed for fractionation of soluble
and insoluble elemental species. The proposed SWASV method was optimized considering
previously described results by Laschi et al [4] and Rueda-Holgado et al [5]. The soluble
fraction samples were assayed for copper and lead (on site measurements) by the proposed
method during a sampling campaign in a suburban area of Badajoz city (Spain). The results
obtained were contrasted by a lab based standard ICP-MS method. The results showed the
potential of SPGE based detection strategy for on site determination of soluble Cu(II) and
Pb(II) in atmospheric deposition.
References
[1].- Viana et al. Aerosol Science 39 (2008) 827-849; [2].- Ballesteros-Gómez A. and Rubio
S. Anal. Chem. 83 (2011) 4579-4613; [3].- Rueda-Holgado F., Palomo-Marín M.R., CalvoBlázquez L., Cereceda-Balic F., Pinilla-Gil E. Talanta (2014) In Press; [4].- Laschi S.,
Palchetti I., Mascini M. Sensors and Actuators B 114 (2006) 460-465; [5].- Rueda-Holgado
F., Bernalte E., Palomo-Marín M.R., Calvo-Blázquez L., Cereceda-Balic F., Pinilla-Gil E.
Talanta 101 (2012) 435-439.
Acknowledgments
This work is supported by the Spanish Ministry of Science and Innovation (project CTQ201125388), Gobierno de Extremadura (GR10091), and the European Union (FEDER). Financial
support from the air quality network of Extremadura (Gobierno de Extremadura, Spain) is
also acknowledged.
204
F-24
Voltammetric Determination of 8-Nitroquinoline at Silver Solid
Electrode in Model Samples of Drinking and River Water
Tereza Rumlova and Jiri Barek
Charles University in Prague, Faculty of Science, University Research Centre UNCE “Supramolecular
chemistry”, Department of Analytical Chemistry, UNESCO Laboratory of Environmental Electrochemistry,
Hlavova 2030/8, 128 43 Prague 2, Czech Republic ([email protected])
This study is focused on the application of a silver solid electrode for the development of
modern voltammetric methods for the determination of submicromolar concentrations of
biologically active compounds present in the environment (8-nitroquinoline (8-NQ) was
chosen as a model substance). 8-NQ is classified as nitrated aromatic heterocyclic compound
and it is well known for its cancerogenity [1]. Silver solid electrode was studied for the sake
of comparison with silver solid amalgam electrodes [2] and has been already voltammetrically
tested for determination of other nitro-compounds [3]. The advantages of silver solid
electrode are primarily its wide potential window in cathodic region, relatively high signals
obtained and low noise of measurements. Other advantage of silver solid electrode are also
non-toxicity compared to mercury electrodes. The optimal conditions for submicromolar
determination of 8-NQ using modern voltammetric methods, namely differential pulse
voltammetry (DPV) and direct current voltammetry (DCV), at a silver solid electrode were
found. This determination is based on cathodic reduction of present nitrogroup. DPV was
chosen for determination of 8-NQ in model samples of drinking and river water. All these
measurements were made in medium of Britton-Robinson buffer of pH 3.0, which was
optimized at first. Using these optimal conditions, it was confirmed that it is possible to
determine 8-NQ in concentration ranges from 2 to 100 μmol L-1 by DPV. This work has
proven practical applicability of silver solid electrode for the determination of micromolar
concentrations of 8-NQ based on cathodic reduction of present nitrogroup in model samples
of drinking and river water.
This research was carried out in the framework of the Specific University Research
(SVV 2014). Financial support from the Grant Agency of the Czech Republic (Project
P206/12/G151) is gratefully acknowledged.
____
[1] M. Takahashi, T. Shirai, S. Fukushima, K. Hosoda, S. Yoshida, N. Ito, Cancer Lett. 1978, 4, 265.
[2] A. Danhel, J. Barek, Curr. Org. Chem. 2011, 15, 2957.
[3] T. Navratil, J. Barek, S. Fasinova-Sebkova, Electroanalysis 2009, 21, 309.
205
F-25
Adsorptive stripping determination of folic acid using the in situ
plated bismuth film electrode
Iwona Rutyna
Faculty of Chemistry, Maria Curie-Sklodowska University, Maria Curie-Sklodowska Sq. 3,
20-031 Lublin, Poland
[email protected]
Folic acid is a water soluble vitamin that belongs to the B-vitamin group.
Deficiency of folic acid and its derivatives, the folates, leads for instance to megaloblastic
anemia, birth defects, several type of cancer, dementia. Folic acid is required for DNA
synthesis and normal cell division. Its requirement is especially essential during pregnancy
[1]. Because of the fact that folic acid deficiency occurs commonly procedures of its
determination in real samples, such as pharmaceutical preparations or food, are demanded.
Stripping voltammetry is often used in the case of folic acid determination due to the fact that
this method is sensitive, inexpensive and it ensures obtaining low detection limits [2]. Several
types of electrodes have been used in the course of folic acid determination such as mercury
and mercury film electrodes, carbon fiber microelectrodes, single- and multi-walled carbon
nanotube film and paste electrodes, phosphomolybdic-polypyrrole film modified electrode or
lead film electrode. Despite the fact that the lowest values of detection limits were reported
for mercury electrodes there is maintaining tendency to replace hazardous mercury by more
environmentally friendly electrode materials nowadays.
In this communication a new procedure of adsorptive stripping voltammetric
determination of folic acid is described. For the first time the bismuth film electrode was used
in the course of folic acid determination. Metal film was plated in situ on a glassy carbon
substrate from an acetate buffer solution of pH 5.5. For stabilization of Bi(III) added to the
sample solution potassium sodium tartrate was introduced to the supporting electrolyte as it
was shown previously [3]. The electrode preparation and accumulation conditions were
optimised. The measurements were carried out from aerated solutions. The calibration graph
for an accumulation time of 180 s was linear from 5 × 10-10 to 2 × 10-8 mol L-1. The detection
limit was 2 × 10-10 mol L-1. The relative standard deviation for a concentration of 1 × 10-8 mol
L-1 of folic acid was 3.1 %. Interference effect of organic substances and surfactants on folic
acid signal were also studied and satisfactory results were obtained. The proposed procedure
was applied for determination of folic acid in pharmaceutical preparations. The obtained
results are in the agreement with values reported by producers and indicate that the proposed
procedure can be applied to folic acid determination in pharmaceutical formulations.
References
[1] J. Zempleni, R. B. Rucker, D. B. McCormick, J. W. Suttie, Handbook of Vitamins 4th ed.,
2007
[2] J. Wang, Stripping Analysis, VCH, Deerfield Beach, FL 1985
[3] M. Korolczuk, A. Moroziewicz, M. Grabarczyk, Anal. Bioanal. Chem., 382 (2005) 1678
206
F-26
Molybdenum determination by adsorptive stripping voltammetry
using solid lead electrode
Iwona Rutyna, Mateusz Ochab, Mieczyslaw Korolczuk
Faculty of Chemistry, Maria Curie-Sklodowska University, Maria Curie-Sklodowska Sq. 3,
20-031 Lublin, Poland
[email protected]
Molybdenum is a trace element that is essential for plants, animals and humans.
It takes part in the carbon, sulphur and nitrogen metabolic cycles as it is a component of many
enzymes [1]. Although molybdenum is required element, its high concentration can be
hazardous for health. It may cause anemia, anorexia, osteoporosis, hair discoloration and
even death [2]. Because of this fact sensitive and selective procedures of its determination in
real samples are demanded. As an alternative to other methods adsorptive stripping
voltammetry has been used for molybdenum determination because it is sensitive,
inexpensive and gives low detection limits [3]. Several types of electrodes have been used in
the course of molybdenum determination such as mercury, bismuth or lead film electrodes.
The toxicity of mercury and mercury or lead salts employed for the preparation of these films
is the greatest drawback in the practical application of these electrodes. Nowadays there is a
great interest in searching electrode materials that would be much more environmentally
friendly in comparison to commonly used mercury or mercury and lead film electrodes. In
this communication we first report on using new type of electrode – solid lead electrode in the
course of molybdenum determination.
In this communication a new procedure of adsorptive stripping voltammetric
determination of molybdenum is described. For the first time the environmentally friendly
solid lead electrode was used in the course of determination of this element. The
measurements were carried out using acetate buffer solution of pH 4.6 and Alizarin S as a
complexing agent at a concentration of 6 × 10-7 mol L-1. The accumulation conditions were
optimised. The measurements were carried out from aerated solutions. The calibration graph
for an accumulation time of 150 s was linear from 2 × 10-9 to 5 × 10-8 mol L-1. The detection
limit was 1 × 10-9 mol L-1. The relative standard deviation for a concentration of 1.5 × 10-8
mol L-1 of molybdenum ions was 3.4 %. Interference effect of foreign ions and surfactants on
molybdenum signal were also studied. It was found that the majority of studied foreign ions
did not influence the molybdenum signal. The proposed procedure was applied for
determination of molybdenum in certified reference material NASS – 5 (sea water). The
standard addition method was used. The obtained results are in the agreement with certified
values and indicate that the proposed procedure can be applied to molybdenum determination
in natural water samples.
References
[1] Z. Marczenko, R. Lobinski, Pure Appl. Chem. 63 (1991) 1627
[2] D.G. Barceloux, Clin. Toxicol. 37 (1999) 231
[3] J. Wang, Stripping Analysis, VCH, Deerfield Beach, FL 1985
207
F-27
Application of a renewable silver based mercury film electrode to
the determination of Ti(IV) in water samples
Malgorzata Grabarczyka, Iwona Rutynaa
a
Faculty of Chemistry, Maria Curie-Sklodowska University, Maria Curie-Sklodowska Sq. 3, 20-031
Lublin, Poland
[email protected]
Titanium is a component of various types of rock and its compounds are among the
most stable soil components. Consequently, only small amounts of titanium end up in water
from rock weathering. A considerably high amount of titanium is released to natural water
from stainless steel modification, light alloys, paper and pulp industry. Titanium is often used
in the chemical processing industry because of many desirable features, manly its resistance
to corrosion. Titanium alloys have been increasingly widely used in aviation, aerospace,
shipbuilding and other departments. A commercially significant titanium compound is
titanium dioxide, which is applied as a pigment in paint, synthetics, paper, fiber and cosmetics
production.
For the determination of titanium(IV) in natural water samples, there are several
frequently adopted methods using analytical techniques, among these voltammperometric
methods are recognized as a powerful tool owing to its sensitivity connected with relatively
inexpensive instrumentation. In order to obtain the low detection limit, voltammetry with
adsorptive pre-concentration of complex of determined metal is much superior comparing to
other methods. In the recent years several adsorptive stripping voltammetry (AdSV)
procedures have been developed also for trace titanium analysis using different complexing
agent
The main aim of this work was to set a simple and sensitive electrochemical procedure
for the determination of trace amounts of titanium in natural water samples. The proposed
method is based on adsorptive accumulation complex of Ti(IV)-chloranilic acid at renewable
mercury film silver based electrode Hg(Ag)FE. This kind of electrode is less toxic than the
commonly used hanging mercury drop electrode.
This work have been optimized by selection of optimal conditions, such as selection of
the supporting electrolyte, pH, concentration of the chloranilic acid as the complexing agent,
accumulation potential and time. The additional target was a precise study of the influence on
the titanium voltammetric peak current of organic substances which can be present in the
natural water samples.
The proposed procedure was tested using the optimal conditions for determination of
Ti(IV) in river waters collected from eastern areas of Poland.
208
F-28
Non-enzymatic electrochemical cholesterol sensor based on
multiwall carbon nanotubes/benzyl acetate modified screen-printed
carbon electrode
Susan Sadeghi*, Aziz Garmroodi
Department of Chemistry, Faculty of Science, University of Birjand, Birjand, South Khorasan, Iran
([email protected])
A simple, sensitive and selective non-enzymatic sensor based on multi-walled carbon
nanotubes (MWCNT) on the benzyl acetate modified home-made screen-printed carbon electrode
(MWCNT/BA-SPCE) for determination of total cholesterol has been developed. Electrochemical
behavior of cholesterol on the surface of the modified electrode was studied by cyclic
voltammetry indicated largest enhanced activity of cholesterol at the MWCNT-modified surface.
All the variables involved in the preparation and performance of the modified electrode were
optimized. In a 0.01 M HNO3+0.05 M KClO4 solution, indirect electrochemical oxidation of
cholestrol with the formal potential of 1.4V(vs.Ag/AgCl) was occurred. Differential pulse
voltammetry and amperometry were used for the electrochemical determination of cholesterol at
the biosensor electrode. The sensitivity of the MWCNT/BA-SPCE was 2.6 μA μM-1 with a linear
response in the range from 0.1 to 7.0 μM and a limit of detection 42 nM(S/N=3). The relative
standard deviation (RSD%) for five determination of 1.0 μM cholesterol was 1.8%.The probable
interferences in biomatrix were selected to test the selectivity and no significant response from
interfering species such as ascorbic acid and uric acid was observed. Due to the high affinity and
stability of the resulting sensing platform, it was successfully applied in the determination of total
cholesterol in human blood serum samples.
Keywords: Cholesterol; Screen-printed carbon electrode; Differential pulse voltammetry; Nonenzymatic; Multi-walled carbon nanotubes
References
[1] S. Qiaocui, P. Tuzhi , Z. Yunu ,C. F. Yang, Electroanalysis 2005, 17, 857-861.
[2] A. Ahmadalinezhad, A. Chen, Biosens. Bioelectron. 2011, 26, 4508-4513.
[3] M. Eguílaz, R. Villalonga, L. Agüí, P. Yáñez-Sedeño, J.M. Pingarrón, J. Electroanal. Chem.
2011, 661, 171–178.
209
F-29
A new amprometric benzaldhyde biosensor based on aldehyde
oxidase immobilized on Fe3O4-graphen oxide/ polyvinylpyrrolidone
/polyaniline nanocomposite
Susan Sadeghi a, *, Ebrahim Fooladi,a Mohammad Malekanehb
a
Department of Chemistry, Faculty of Science, University of Birjand, Birjand, South Khorasan, Iran
([email protected])
Department of Clinical Biochemistry, Birjand University of Medical Sciences, Birjand, South Khorasan, Iran
b
A new biosensor for determination of benzaldehyde based on carbon past electrode modified
with a nano composite was developed. The nano composite of Fe3O4-graphen oxide/ polyvinyl
pyrrolidone/ polyaniline (Fe3O4-GOX/PVP/PANI) was assembled onto the surface of electrode
via electrodeposition. Furthermore, crude extract aldehydel oxidase isolated from rat liver was
immobilized on the Fe3O4-GOX/PVP/PANI nanocomposite. The cyclic voltammetry and
impedance spectroscopy studies of the modified electrode indicated that Fe3O4/GOX can be used
as an electron mediator. Moreover, it has excellent electrocatalytic activity for hydrogen peroxide
reduction. The presence of polyvinyl pyrrolidone in the nanocomposite could substantially
improve the dispersibility of graphen, leading to enhanced sensitivity of the electrode. The
resulted biosensor was employed to determine benzaldhyde amperometrically based on reduction
of produced hydrogen peroxide at -0.25 V (vs. Ag/AgCl). In correspondence with the substrate
selectivity of the enzyme in solution, the biosensor revealed a preference for aromatic aldehydes
than aliphatic aldehydes. Under the optimum conditions, the biosensor exhibited a linear response
to benzaldehyde concentration in the range of 0.5-50 μM with a limit of detection of 0.4
μM(S/N=3), sensitivity of 0.812 μA μM-1, and fast response time of 10s. The new biosensor
showed good performance to analysis of benzaldhyde in real samples such as drugs and food.
Keywords: Benzaldhyde; Aldhyde oxidase; Crude extract; Nanocomposite; Carbon paste
biosensor.
[1]M. E. Ghica, R. Pauliukaite, N. Marchand, E. Devic, C. M.A. Brett, Anal. Chim. Acta, 2006,
591, 80.
[2] H. Teymourian, A. Salimi, S. Khezrian, Biosens .Bioelectro,2013, 49 ,1.
[3] A. Badalyan, M. Neumann, S. Leimkoler, U. Wollenberger, Electroanalysis 2013, 25,11.
210
F-30
Direct Electrochemistry of nitrous oxide reductase from
Marinobacter hydrocarbonoclasticus at a carbon nanotube
modified glassy carbon electrode
Cíntia Carreira1, Sofia R. Pauleta1, Isabel Moura1, Margarida M. C. dos Santos2
1
REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de
Lisboa, 2829-516 Caparica, Portugal.
Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001
Lisboa, Portugal.
2
Nitrous oxide (N2O) is a potent greenhouse gas and its emission to the atmosphere has been
enhanced in the last century through the intensification of agriculture. In nature, N2O can only
be converted to N2 by a copper dependent enzyme namely nitrous oxide reductase (N2OR), in
a metabolic pathway known as denitrification.
N2OR is a functional homodimeric enzyme containing two multicopper centers, CuA, the
electron transferring (ET) center and CuZ the catalytic (C) center. CuZ is a tetranuclear
copper center, bridged by one or two sulfide ions, unique in biology, that can have different
oxidation states [2Cu2+-2Cu+], [1Cu2+-3Cu+] and [4Cu+] (1).
In the last years, different redox states of N2OR from Marinobacter hydrocarbonoclasticus
have been isolated and biochemically characterized (2). Recently we reported the mediated
electrochemical study of N2OR from Marinobacter hydrocarbonoclasticus with its
physiological electron donor, cytochrome c-552 (3).
In this work we now report the first direct electrochemical response under non-turnover
conditions of N2OR from Marinobacter hydrocarbonoclasticus. The redox properties of the
enzyme were analyzed by cyclic voltammetry with the enzyme molecules confined to the
surface of a carbon nanotube modified glassy carbon electrode.
References:
1. S. R. Pauleta, S. Dell'acqua, I. Moura. Nitrous oxide reductase. 2013. Coordination
Chemistry Reviews. 257(2): 332-349.
2. S. Dell'acqua, S. R. Pauleta, J.J.G. Moura, I. Moura. Biochemical characterization of the
purple form of Marinobacter hydrocarbonoclasticus. 2012. Philos. Trans. R. Soc. B - Biol.
Sci. 367(1593): 1204-12.
3. S. Dell’Acqua, S. R. Pauleta, P.M. Paes de Sousa, E. Monzani, L. Casella, J.J.G. Moura, I.
Moura. A new CuZ active form in the catalytic reduction of N2O by nitrous oxide reductase
from Pseudomonas nautica. 2010. J. Biol. Inorg. Chem. 15 (6):967-76.
Acknowledgments: We thank Fundação para a Ciência e Tecnologia for financial support to
CC (SFRH/BD/87898/2012), IM (PTDC/QUI-BQ/116481/2010), SRP and MMCS
(PTDC/BIA-PRO/109796/2009)
211
F-31
Interactions of Flavonoids with Lipid Monolayers
Didem Sanver, Brent S. Murray and Andrew Nelson*
School of Food Science and Nutrition ([email protected])
*School of Chemistry, University of Leeds, UK
Leeds, LS2 9JT
Abstract
Flavonoids are a general class of polyphenol substances that are believed to have healthy
benefits to the body in terms of their antioxidant capacity and various other
interactions. However, many of the most widespread and efficacious of them are actually not
very soluble in water, or oil, and some of them are present as glycosidic derivatives, i.e., with
sugar residues attached. Enzymes in the gut cleave off the sugars, which decreases their
solubility but aids their passive (or active) transport through the brush border membrane, or
through the tight junctions. However, little is known in detail about how flavonoids interact
with such membranes. Thus, it is highly important to investigate the underlying molecular
properties that determine flavonoid interactions with biomembranes in order to understand
their adsorption pathways. For this purpose, the interactions between flavonoids and a
dioleoyl phosphatidylcholine (DOPC) monolayer on the mercury (Hg) film electrode have
been investigated using rapid cyclic voltammetry (RCV). Among the flavonoids studied,
quercetin, kaempferol and tiliroside showed strong interactions with DOPC, whereas a wide
range of other flavonoids exhibited limited interaction. The results suggest that binding or
penetration of different flavonoids into the membrane depends on the number of hydroxyl
groups as well as their chemical structure. The study will be currently carried out with
Langmuir monolayers as comparison and validation of the electrochemical work and is
being extended to polymer supported Caco-2 epithelial cells, in order to gain a better
understanding of the physicochemical mechanisms underlying flavonoid interaction with
membranes.
212
F-32
An electronic tongue using cellobiose dehydrogenases from
different origins to discriminate various sugars and interfering
analytes
Christopher Schulza, Andrea Ciprib, Manel del Valleb, Roland Ludwiga and Lo Gortona
a
Lund University, Department of Biochemistry and Structural Biology, P. O. Box 124, SE-22100 Lund,
Sweden, ([email protected], [email protected])
b
Sensors & Biosensors Group, Department of Chemistry, Universitat Autònoma de Barcelona,
Edifici Cn, 08193 – Bellaterra, Spain
Cellobiose dehydrogenase (CDH, EC 1.1.99.18) is an extracellular fungal redox enzyme,
which has shown promising properties for applications in both biosensors and biofuel cells
[1,2]. It is a two domain enzyme composed of a catalytic, FAD containing domain, DHCDH,
connected through a polypeptide linker region with a cytochrome b domain, CYTCDH. In the
catalytic reaction, the substrate is oxidised at the DHCDH, which in turn is reoxidised through
an intramolecular and sequential electron transfer process donating the electrons to the
CYTCDH, from which the electrons can be donated directly to an electrode. The substrate
spectrum of CDH is rather broad including, depending on the origin of CDH, also various
analytically relevant sugars such as glucose, maltose and lactose [1,2]. Recently we also
found a beneficial effect of divalent cations on the electroactivity of CDH but making them in
the same run a possible interfering species [3]. Oxygen has also been shown to be a possible
electron acceptor for CDH, however to a very limited extend [4].
To overcome these specificity limitations different CDHs of various origins, having different
specificities to substrates and interfering analytes, will be used in a multi electrode
arrangement as an electronic tongue, to perform determination and resolution of a mixture of
saccharides. Such an electrode array is trained first with all possible analytes and interfering
species to obtain an analyte-response matrix including all the voltammetric responses. This
data matrix will be processed with the use of artificial neural networks, to perform later
determination of unknown samples.
In this context, the concept of utilising CDH in an electronic tongue arrangement as well as its
first results will be presented.
[1] R. Ludwig, W. Harreither, F. Tasca, L. Gorton, ChemPhysChem, 2010, 11, 2674
[2] R. Ludwig, R. Ortiz, C. Schulz, W Harreither, C. Sygmund, L. Gorton, Anal Bioanal
Chem, 2013, 405, 3637
[3] C. Schulz, R. Ludwig, P. O. Micheelsen, M. Silow, M. D. Toscano, L Gorton,
Electrochem Comm, 2012, 17, 71-74
[4]C. Sygmund, P. Santner, I. Krondorfer, C. K. Peterbauer, M. l. Alcalde, G. S. Nyanhongo,
G. M. Guebitz, R. Ludwig, Microb Cell Fact, 2013, 12, 38
213
F-33
Electrochemical behavior and voltammetric determination of
folates folic acid and leucovorin and antifolate methotrexate using
bare boron-doped diamond electrode
Renáta Šelešovská, Lenka Bandžuchová, Jaromíra Chýlková
Institute of Environmental and Chemical Engineering, University of Pardubice, Studentská 573, 530 09
Pardubice, Czech Republic ([email protected])
Folates are significant bioactive compounds which are derived from folic acid. Their structure
is based on L-pteroylglutamic acid (Fig. 1). The human body cannot synthetize paminobenzoyl acid or link glutamate with pteridine ring. Folates have to be received from
food. Folic acid (FA, CAS: 59-30-3) is essential compound belonging to the vitamin group of
B-complex (B9). Folic acid or folates in general are enzymatically transformed into their
biologically active form tetrahydrofolates (THF). THF participates transferring of one-carbon
groups which are necessary for DNA and RNA biosynthesis, red blood cells formation and
methylation processes in organism. Methotrexate (Ametopterin, MTX, CAS: 59-05-2) is an
analog of FA which differs only in the presence of a methyl group forming a bridge between
the amino group of amino benzoic acid (N(10)) and the amino group substituted on C(4) on
the pyridine circle. MTX inhibits the enzyme dihydrofolate reductase and that is why MTX is
called antifolate. In this way MTX blocks the purine synthesis in all cells, prohibits their
further division and also leads to damage. Due to the rapid division of cancer cells, especially
their damage is the greatest. Therefore, MTX is an important chemotherapeutic drug.
Leucovorin (folinic acid, LV, CAS: 58-05-9) acts as an antidote of MTX. It is one of the
reduced derivatives of folic acid, which is often used in treatment of very serious diseases like
cancer or some inflammatory diseases.
The possibility of application of bare boron-doped diamond electrode (BDDE) in
voltammetric analysis of the above mentioned compounds has been investigated. Cyclic
voltammetry and direct current voltammetry has been used for study of its voltammetric
behavior. Differential pulse voltammetry has been
applied for development of sensitive methods of
determination for tested electroactive compounds.
Various statistical parameters, e.g., relative
standard deviations of repeated measurements or
limits of detection, were calculated. The proposed
methods were successfully applied for analysis of
real samples of vitamin products and drugs.
Fig. 1 Scheme of L-pteroylglutamic acid
Acknowledgement
This work was supported by The Ministry of Education, Youth and Sports of the Czech Republic
(project No. CZ.1.07/2.3.00/30.0021).
Reference
Voet D., Voetová J. G.: Biochemie. Victoria Publishing, Prague 1994.
Jolivet J.: Eur. J. Cancer 31A, 1311-1315 (1995).
214
F-34
Surface developed molecularly imprinted polymer
for enantioselective sensing
Piyush Sindhu Sharma,1 Marcin Dabrowski,1 Krzysztof Noworyta,1 Alexander Kuhn,2
Francis D’Souza,3 and Wlodzimierz Kutner,1,4
1. Department of Physical Chemistry of Supramolecular Complexes, Institute of Physical Chemistry, Polish
Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
2. University of Bordeaux 1, Bordeaux, France
3. Department of Chemistry, University of North Texas, Denton, TX 76203-5017, USA
4. Faculty of Mathematics and Natural Sciences, School of Science, Cardinal Stefan Wyszynski University in
Warsaw, Wóycickiego 1/3, 01-815 Warsaw, Poland
[email protected]
Molecular imprinting in polymers is a well-established procedure for preparing
artificial recognition units of chemical sensors. This procedure can produce materials of
selectivity comparable to that of their biological counterparts. We use this technique of
preparation of synthetic receptor for our anlayte of choice, arabitol, a sugar alcohol.
Selective determination of chiral sugars in biological samples is challenging. For that,
molecularly imprinted polymer (MIP) films are promising as recognition units of
chemosensors for enantioselective determination of such compounds, like D- and L-arabitol
sugar alcohols.
Generally, thin film of a molecularly imprinted polymer (MIP) deposited directly on
surface of the transduction unit to integrate these recognition units to result in a chemical
sensor. However, slow diffusion of analyte towards less accessible imprinted molecular
cavities in continuous film restricts the sensitivity of such sensing system. Additionally,
continuous film produces a low specific surface area. Therefore, specific surface area should
be increased in a controllable way by developing the film surface for enhancement of
transduction signal.
We report here preparation and application of porous electropolymerized MIP films
as recognition unit. For that, first step involves assembling of silica colloidal sphere onto Au
coated quartz crystal resonator surface via Langmuir–Blodgett technique. Second step
involves potentiodynamic electrochemical deposition of the pre-polymerization complex of
arabitol, functional monomer and cross-linker. 2,2’-Bithiophene derivatized with boronic acid
served here as a functional and 3,3’-bithiophene as a cross-linker monomers. After
electropolymerization, sacrificial silica was removed by 1% HF solution. For template Larabitol removal 0.1 M HCl was used. Binding of isomeric analytes towards it corresponding
recognition sites were transduced with help of quartz crystal microbalance. Analytical
performance of the chemosensors, including detectability, selectivity, and sensitivity, was
determined under flow injection analysis condition.
215
F-35
Macroporous Bismuth Film Electrodes Prepared on a ScreenPrinted Substrate Electrode for the Simultaneous Determination
of Ni(II) and Co(II)
Hanna Sopha, Sebastiano Dal Borgo*, Radovan Metelka, Samo Hočevar* and Ivan Švancara
Department of Analytical Chemistry, Faculty of Chemical Technology, University of Pardubice, CZ-532 10
Pardubice, Czech Republic, ([email protected])
* Analytical Chemistry Laboratory, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia
Almost a century known voltammetric stripping analysis is still an attractive technique for the
determination of heavy metal ions. In the previous decades, it was combined mainly with
mercury based electrodes; usually, with the hanging mercury drop electrode (HMDE) or
mercury film electrode (MFE). Less toxic electrode materials with comparable electrochemical behaviour to mercury have also been proposed; typical example being the successful
introduction of bismuth-coated electrode [1]. Being known as “green” element thanks to its
low toxicity, bismuth exhibits similar electrochemical properties like mercury and due to its
compact character, solid bismuth offers also some specifics compared to liquid mercury [2].
Up until now, bismuth electrodes have been used in a variety of modifications; e.g., in- or exsitu prepared film electrodes on different substrate electrodes, bismuth bulk electrode and
bismuth-powder or bismuth-salt modified carbon paste electrodes [2].
About three years ago, for the first time, a macroporous bismuth film electrode (mpBiFE) has
been presented [3]; again, in combination with anodic stripping voltammetry (ASV). Due to
the macro-porous structure of the electrode surface, the active area was significantly
increased, resulting in the improved detection limits for selected analytes.
In this contribution, we present our recent investigations on the macroporous BiFE
configuration prepared by plating the film onto a screen-printed electrode (SPE) substrate and
intended for the determination of Ni(II) and Co(II) by adsorptive stripping voltammetry. In
order to prepare the macroporous structure of the sensing element, initially polystyrene
microspheres had been deposited onto the SPE substrate acting as a template. Afterwards,
bismuth was electrochemically plated into the vacancies in the macroporous structure and
consequently, the plastic microspheres dissolved in toluene. In this way, the macroporous
bismuth structure could be obtained, serving as the electrode proper. After optimization of
some key parameters, the mpBiFE revealed potentially attractive electroanalytical
performance in the ASV mode, characterised also by LODs of 0.22 μg L-1 Ni(II) and and 0.57
μg L-1 Co(II), respectively.
Acknowledgement
A financial support from the Ministry of Education, Youth, and Sports of the Czech Republic (Project
CZ.1.07/2.3.00/30.0021 “Enhancement of R&D Pools of Excellence at the University of
Pardubice“) is gratefully acknowledged.
References
[1] J. Wang, J. Lu, S. B. Hocevar, P. A. M. Farias, B. Ogorevc, Analytical Chemistry 72 (2000) 218.
[2] I. Svancara, C. Prior, S.B. Hocevar, J. Wang, Electroanalysis 22 (2010) 1405.
[3] V. Urbanova, M. Bartos, K. Vytras, A. Kuhn, Electroanalysis 22 (2010) 1524.
216
F-36
Application of Bismuth film screen-printed electrode to study the
metal complexation by thiol-rich peptides
Velia Sosa, Núria Serrano, Cristina Ariño, José Manuel Díaz-Cruz and Miquel Esteban
Departament de Química Analítica. Facultat de Química. Universitat de Barcelona.
Martí i Franquès 1-11, E – 08028 – Barcelona (Spain). Phone: (34) 93 403 91 24. Fax: (34) 93 402 12 33.
[email protected]
Glutathione (J-Glu–Cys–Gly, denoted usually as GSH) and its oligomers named
phytochelatins ((J-Glu–Cys) n–Gly, denoted usually as PCn, where n generally ranges from 2
to 5) are thiol-rich peptides which are synthesized enzymatically by plants in response to an
excessive uptake of certain heavy metal ions. The great affinity of the thiol group for heavy
metals makes important the complexation by these thiol containing peptides not only for
heavy metal detoxification but also for phytoremediation purposes.
To study the complexation of metals as Cd(II), Zn(II), Pb(II), Cu(II) with such peptides, the
combined use of voltammetric techniques and chemometric methods as Multivariate Curve
Resolution by Alternating Least Squares (MCR-ALS) and/or Gaussian Peak Adjustment
(GPA) has proved to be useful. However, certain metal-thiol peptides systems present the
difficulty that thiol favors the electrodic oxidation of the mercury of the electrode. This
process generates anodic signals that are strongly overlapping with those related with the
metal ion to be studied, making the analysis of these systems even more complicated.
A suitable solution could be the use of electrodes based in other material than mercury,
expecting the non-formation of these signals and therefore the simplification of
electroanalytical data. Bi-based electrodes have the advantage of being environmentally
friendly and they offer some features closest to those of mercury [1-2]. Bi film coated on a
glassy-carbon disk was the most commonly used electrode (BiFE), although the progress of
the screen-printing technique achieved in recent years has facilitated the development of
disposable Bi-coated screen-printed electrodes (Bi-SPEs) that have increasingly gained
advantage over the more conventional BiFE [3]. Three general methods of coating the
substrate with bismuth are well-known: ex-situ plating or preplated method, in-situ plating
method and “bulk” method.
An advantage of the ex-situ method can be found in its application to metal complexation
studies, where the presence of Bi(III) ions in the medium can seriously disturb the speciation
of the system being examined. Thus, this work evaluates the applicability of an ex-situ
bismuth film on commercial screen-printed carbon electrode (ex-situ BiSPCE) in the study of
the complexation of Cd(II)-GSH and Cd(II)-PC2 systems, and the subsequent treatment with
MCR-ALS or GPA of the obtained voltammetric data, allowing us the establishment of the
stoichiometry of the possible complexes formed [4].
[1] J. Wang, Electroanalysis (NY) 17 (2005) 1341.
[2] A. Economou, Trends Anal. Chem. 24 (2005) 334.
[3] N. Serrano, A. Alberich, J.M. Díaz-Cruz, C. Ariño, M. Esteban, Trends Anal. Chem. 46
(2013) 15.
[4] V. Sosa, N. Serrano, C. Ariño, J.M. Díaz-Cruz, M. Esteban, Talanta 107 (2013) 356.
217
F-37
A voltammetric study of the interactions of pesticides with
phospholipid structures
Jitka Součková, Hana Švecová, Eva Marková, Pavla Macíková, Jakub Táborský, Jana
Skopalová and Petr Barták
Department of Analytical Chemistry, Regional Centre of Advanced Technologies and Materials, Faculty of
Science, Palacký University, 17. listopadu 12, 77146 Olomouc, Czech Republic ([email protected])
Pesticides are known to interact with phospholipid layers and fatty acids in membrane
structures and strongly accumulate in lipid tissues. Paraquat, a bipyridinium electroactive
pesticide, served as a model compound for this purpose. Asolectine, phospholipid mixture
from soybeans, was used for preparation of phospholipid aggregates.
Ability of paraquat to interact with phospholipid structures was evaluated from changes in
paraquat distribution between aqueous and phospholipid phase in samples with different
asolectine concentration. After separation of both phases by micro-ultracentrifugation,
paraquat was determined in the aqueous phase. Voltammetry on glassy carbon electrode was
used for quantitative determination of electroactive pesticide remaining in aqueous phase. The
observed changes of pesticide content were used for evaluation of distribution equilibria of
lipophilic substance between phospholipid aggregates and water (buffer).
The authors gratefully acknowledge the financial support by the Operational Program Education for
Competitiveness – European Social Fund (project CZ.1.07/2.3.00/20.0018) and by the Operational
Program Research and Development for Innovations - European Regional Development Fund (project
CZ.1.05/2.1.00/03.0058). The work has been also supported by the project of Palacký University in
Olomouc IGA_PrF_2014031 and the Czech Science Foundation project P206/12/1150.
218
F-38
Biocathode in self-powered system for dioxygen monitoring
Krzysztof Stolarczyk, Michał Kizling, Renata Bilewicz*
e-mail address: [email protected]
*Faculty of Chemistry, University of Warsaw, Pasteura 1, Warsaw 02-093, Poland
The increasing industrialization and pollution of natural environment calls for
fast and cost-effective analytical techniques to be used in monitoring programs. The need for
simple and specific systems or tools for environmental applications, in particular for
environmental monitoring but also for medical use has encouraged the development of new
and more suitable methodologies. In our laboratory we focus on self - powered systems which
can work as a source of power and as a biosensor. We describe the design of a stack of
biobatteries powering dioxygen biosensor, as a prototype for medical or environmental usage.
Power generation was achieved by employing laccase based dioxygen reducing cathodes and
zinc anode, thereby creating a zinc/dioxygen BFC [1,3]. In order to be able to utilize the BFC
as a power supply for sensors, a suitable micro – potentiostat was designed to collect the
analytical signal from the biosensor. The operation of the developed device was investigated
in buffer solution containing different dioxygen concentrations. The biocathode worked as the
source of power and as a biosensor for monitoring dioxygen levels.
References
1. K. Stolarczyk, M. Sepełowska, D. Łyp, K. Żelechowska, J.F. Biernat, J. Rogalski, K.D.
Farmer, K.N. Roberts, R. Bilewicz, Bioelectrochem. 87 (2012) 154.
2. K. Stolarczyk, D. Łyp, K. Żelechowska, J.F. Biernat, J. Rogalski, R. Bilewicz, Electrochim.
Acta 79 (2012) 74.
3. K. Stolarczyk, M. Kizling, D. Majdecka, K. Żelechowska, J.F. Biernat, J. Rogalski, R.
Bilewicz, J. Power Sources 249 (2014) 263.
219
F-39
Modified glassy carbon platform as a guanine sensor
Sylwia Strzalkowska1, Wioleta Dzialak1, Tomasz Sokalski2, Andreas Ebner3, Andrzej
Lewenstam2,4, Magdalena Maj-Zurawska1
1
University of Warsaw, Department of Chemistry, Pasteura 1, 02-093 Warsaw, Poland;
([email protected]),
Process Chemistry Centre, c/o Centre for Process Analytical Chemistry and Sensor Technology (ProSens), Åbo
Akademi University, Biskopsgatan 8, 20500 Åbo-Turku, Finland;
3
Biophysics Institute, Johannes Kepler University Linz, Guberstrasse 40, 4020 Linz, Austria;
4
Department of Materials Science and Ceramics, Interdisciplinary Centre of Materials Modelling, AGHUniversity of Science and Technology, Al. Mickiewicza 30, 30-059 Krakow, Poland;
2
In the last couple of decades, increasing interest in electrochemical biosensors, especially
containing various forms of deoxyribonucleic acid (DNA), has been noticed due to their wide
range of possible applications, from the detection of disease-causing and food-contaminating
organisms to forensic and environmental research. Guanine (G) posses the lowest redox
potential of the four bases found in DNA, and its electrochemical oxidation signal is therefore
the most easily observed during nucleic acid oxidation. Changes in G concentrations, the
kinetics of electron-transfer reactions or its oxidation potential, are considered indicators of
various mutations in the immune system as well as various interactions with chemical
compounds.1-3
The improved electrochemical behaviour of guanine was achieved by applied nanomaterials
on glassy carbon platform, and by this, the attractive properties, were exposed.
In this work, the glassy carbon platform covered by a layer of multiwall carbon nanotubes
(MWCNTs) or platinum nanoparticles were used in the ordered architecture of the matrices
holding guanine. To compare both system various electrochemical methods such as cyclic
voltammetry (CV), differential pulse voltammetry (DPV), electrochemical impedance
spectroscopy (EIS), and scanning microscopes such as SEM and AFM were used.
The presented data clearly indicate that the unbounded or bonded guanine oxidation process
depends on preparation and the modifications of the surface of working electrode,
accumulation potential, time of adsorption and scan rate. It is important since these redox
reactions involve unstable radicals, intermediates, and dimers. The oxidation signal of
guanine and the behavior with typical redox indicator, Methylene Blue, was also investigated.
References
(1) D. Maciejewska, I. Szpakowska, I. Wolska, M. Niemyjska, M. Mascini, M. MajZurawska. Bioelectrochemistry 2006, 69, 1.
(2) A. Palinska, A. Grodzka, H. Elzanowska, B. Kepska, E. Zwierkowska, S. Achmatowicz,
M. Maj-Zurawska. Electroanal. 2010, 22, 1306.
(3) A. Gniazdowska, A. Palinska-Saadi, E. Krawczyk, H. Elzanowska, M. Maj-Zurawska.
Bioelectrochemistry 2013, 92, 32.
220
F-40
,QIOXHQFHRISKRVSKROLSLGOD\HURQWKHVHOHFWLYLW\RIJODVV\FDUERQ
HOHFWURGHIRUWKHGHWHUPLQDWLRQRISDUDTXDW
+DQDâYHFRYi-LWND6RXþNRYi(YD0DUNRYi3DYOD0DFtNRYi-DNXE7iERUVNê-DQD
6NRSDORYi3HWU%DUWiN
'HSDUWPHQWRI$QDO\WLFDO&KHPLVWU\5HJLRQDO&HQWUHRI$GYDQFHG7HFKQRORJLHVDQG0DWHULDOV)DFXOW\RI
6FLHQFH3DODFNê8QLYHUVLW\OLVWRSDGX2ORPRXF&]HFK5HSXEOLFKDQNDVYHF#VH]QDPF]
3DUDTXDW LV RQH RI WKH PRVW ZLGHO\ XVHG SHVWLFLGHV IRU FRQWURO RI ZHHGV LQ WKH ZRUOG ,W LV
TXLFNDFWLQJ DQGQRQVHOHFWLYHNLOOLQJJUHHQSODQWWLVVXHRQFRQWDFW,WLVH[WUHPHO\WR[LFWR
KXPDQ DQG DQLPDOV 3DUDTXDW DQG LWV UHVLGXHV DUH VWURQJO\ DGVRUEHG LQ WKH VRLO WKH\ ELQG
HVSHFLDOO\ WR FOD\ PLQHUDOV DQG KXPLF DFLGV $QDORJRXVO\ WR RWKHU VWURQJO\ DGVRUEHG
SHVWLFLGHV SDUDTXDW WHQGV WR DFFXPXODWH LQ WKH HQYLURQPHQW 7KHUHIRUH LW LV QHFHVVDU\ WR
PRQLWRUWKHFRQWHQWRIWKLVVXEVWDQFH
(OHFWURFKHPLFDO DFWLYLW\ RI SDUDTXDW FDQ EH XVHG IRU LWV YROWDPPHWULF GHWHUPLQDWLRQ ,Q WKLV
FRQWULEXWLRQXWLOLVDWLRQRIJODVV\FDUERQHOHFWURGHPRGLILHGE\SKRVSKROLSLGOD\HU/0*&(
IRUWKLVSXUSRVHLVGHVFULEHG,WZDVREVHUYHGWKDWWKHSKRVSKROLSLGOD\HUVXSUHVVHGHIIHFWLYHO\
WKH FXUUHQW UHVSRQVH RI VRPH K\GURSKLOLF HOHFWURDFWLYH VSHFLHV VXFK DV FRSSHU LRQV HYHQ LQ
WKHLU ODUJH H[FHVV WR SDUDTXDW %\ FRQWUDVW WKH FXUUHQW UHVSRQVH RI OLSRSKLOLF SDUDTXDW ZDV
DOPRVW XQDIIHFWHG E\ WKH SKRVSKROLSLG OD\HU 6R WKDW /0*&( FDQ EH XVHG IRU VHOHFWLYH
GHWHFWLRQRISDUDTXDWLQWKHSUHVHQFHRIK\GURSKLOLFVXEVWDQFH'LIIHUHQWLDOSXOVHYROWDPPHWU\
ZDVXVHGIRUWKHGHWHUPLQDWLRQRIPLFURPRODUFRQFHQWUDWLRQRISDUDTXDWLQWKHPL[WXUHZLWK
FRSSHUVXOSKDWH
7KHDSSURDFKFDQEHXVHGIRULQFUHDVLQJRIVHOHFWLYLW\RIDQDO\WLFDOPHWKRGVIRUGHYHORSPHQW
RI HOHFWURFKHPLFDO VHQVRUV DV ZHOO DV LQ UHVHDUFK RI SKRVSKROLSLG DJJUHJDWHV DQG LWV
SURSHUWLHV
$FNQRZOHGJHPHQW
7KH DXWKRUV JUDWHIXOO\ DFNQRZOHGJH WKH ILQDQFLDO VXSSRUW E\ WKH 2SHUDWLRQDO 3URJUDP
5HVHDUFKDQG'HYHORSPHQWIRU,QQRYDWLRQV(XURSHDQ5HJLRQDO'HYHORSPHQW)XQG3URMHFW
&= DQG E\ WKH 2SHUDWLRQDO 3URJUDP (GXFDWLRQ IRU &RPSHWLWLYHQHVV ±
(XURSHDQ 6RFLDO )XQG3URMHFW&=7KH ZRUN KDV EHHQ DOVR VXSSRUWHG
E\ WKH SURMHFW RI 3DODFNê 8QLYHUVLW\ LQ 2ORPRXF ,*$B3U)BDQG WKH &]HFK 6FLHQFH
)RXQGDWLRQSURMHFW3
221
F-41
Cytochrome c biosensor based on liquid crystalline cubic phase
doped with cytochrome c reductase
Monika Szlęzak, Ewa Górecka, Renata Bilewicz
University of Warsaw, Faculty of Chemistry
[email protected]
Cubic phase formed by mixing glycerol monooleate with water can find application in
biosensing. Lipidic mesophase is a useful matrix to host redox enzymes, since it preserves
native structure and bioactivity of the proteins and can be spread in form of a thin film at the
electrode surface. The most crucial step in the biosensor construction is the appropriate
immobilization of protein in the mesophase film in order to avoid aggregation, denaturation or
degradation, e.g. upon contact with a metallic electrode. Liquid crystalline matrix was shown
by us to allow direct electron transfer between some redox enzymes and the electrode [1]. So
far we used the cubic phase for encapsulation of water soluble enzymes e.g. laccase. The
cubic phase possesses also lipidic domains allowing the immobilization of membrane proteins
such as cytochrome c reductase (CcR, complex III). This enzyme is the part of the
mitochondrial respiratory chain crucial for the metabolic pathways in living cells. CcR is
responsible for the transfer of electrons from ubiquinol to cytochrome c (Cyt c), which is an
electron donor to complex IV.
Small Angle X–ray Scattering is employed for the characterization of the cubic phase without
and with the enzyme. The electrochemistry of membrane protein incorporated into the lipidic
cubic phase film was studied using glassy carbon electrode as the substrate. The biosensor is
employed for the determination of cytochrome c.
[1] Ewa Nazaruk, Renata Bilewicz, Göran Lindblom, Britta Lindholm-Sethson “Biosensors
based on Cubic Phases”, Anal Bioanal Chem, 2008,391,1569-1578
222
F-42
Electrochemical oxidation of zopiclone
Jakub Táborský, Martin Švidrnoch, Pavla Macíková, Hana Švecová, Eva Marková, Jitka
Součková, Jana Skopalová
Department of Analytical Chemistry, Regional Centre of Advanced Technologies and Materials, Faculty of
Science, Palacký University, 17.listopadu 12, 771 46 Olomouc, Czech Republic ([email protected])
Zopiclone (ZOP) is a non-benzodiazepine short-acting hypnotic drug. It is a cyclopyrrolone
derivative belonging to a novel chemical class which is structurally unrelated to existing
hypnotics. The muscle relaxant and anticonvulsant properties of ZOP are used for the
treatment of insomnia [1-3]. The metabolism of ZOP proceeding in the human liver by
cytochrome P450 gives rise to two main metabolic products: N-desmethyl-zopiclone and Noxide-zopiclone [4]. The second product suggests oxidisability of ZOP.
Electrochemical oxidation of ZOP on a glassy carbon electrode has already been studied using
adsorptive stripping voltammetry by Yilmaz [5], but without any further investigation of the
electrochemical process. In presented work, electrochemical behaviour of ZOP was
investigated using cyclic voltammetry, differential pulse voltammetry and square wave
voltammetry in three-electrode system with the working glassy carbon electrode, reference
saturated calomel electrode and auxiliary platinum electrode. Measurements were performed
in methanol/water solutions at different pH in the range 2 – 11 and at different scan rates.
ZOP provided one oxidation peak over the pH range. Control potential electrolysis of ZOP on
a platinum gauze electrode and following mass spectrometric analysis of oxidation products
were performed to elucidate the oxidation pathway. Online coupling of electrochemistry with
mass spectrometry was also performed by connection of a coulometric flow cell directly to
mass spectrometric interface.
References
[1] Tonon M.A., Jabor V.A.P., Bonato P.S., Anal Bioanal Chem 400 (2011) 3517-3525
[2] Tonon MA., Bonato PS., Electrophoresis 33 (2012) 1606-1612
[3] Jantos R., Vermeeren A., Sabljic D., Remaekers J. G., Skopp G., Int J Legal Med 127 (2013) 6976
[4] Beyquemont L., Mouajjah S., Escaffre O., Beaune P., Funck-Brentano C, Jaillon P.:
DrugMetabDispos 27 (1999) 1068-1073
[5] Yilmaz S.: Colloids and Surfaces B: Biointerfaces 71 (2009) 79-83
Acknowledgements
The authors gratefully acknowledge the financial support by the Operational Program Research and
Development for Innovations - European Regional Development Fund (Project
CZ.1.05/2.1.00/03.0058). The work has been also supported by the project of Palacký University in
Olomouc IGA_PrF_2014031 and the Czech Science Foundation project P206/12/1150.
223
F-43
Towards electrochemical purification of chemically reduced
graphene oxide: redox accessibility of impurities
Shu Min Tan, Adriano Ambrosi, Bahareh Khezri, Richard D. Webster and Martin Pumera*
Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang
Technological University ([email protected])
* Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang
Technological University
Abstract
The electrochemical properties of graphene and related nanocarbon materials have been
shown to be highly sensitive to the residual metallic impurities that persist in the materials
despite various purification efforts. In this study, the partial purification of chemically
reduced graphene oxides obtained from graphite oxide prepared by Hummers (CRGO-HU)
and Staudenmaier (CRGO-ST) oxidation methods was performed via an electrochemical
purification step, followed by cyclic voltammetric scans of cumene hydroperoxide (CHP) in
phosphate buffer solution (PBS). The removal of iron impurities which are electrocatalytic
towards CHP1 were monitored by the changes in the peak current and peak potential of the
CHP reduction peak. The CRGOs pre- and post-purification were characterized by
inductively coupled plasma-mass spectrometry (ICP-MS), electron-dispersive X-ray
spectroscopy (EDS), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy
(XPS) and cyclic voltammetry (CV). The SEM images revealed CRGOs of similar
morphologies, but with greater defects at the edges of CRGO-HU. From the XPS spectra,
reductions in the C/O ratios were observed after electrochemical purification for all materials.
Based on analyses of CHP peak current and peak potential, CRGO-HU exhibits a greater
efficiency of iron impurities removal compared to CRGO-ST. This can be attributed to the
use of strong potassium permanganate oxidant to obtain the graphite oxide precursor of
CRGO-HU, which exposes more defect sites for iron impurities to reside in. This facile
electrochemical purification of graphenes provides an additional option of routine cleaning of
graphene before electrochemical measurements for analytes that show exceptional sensitivity
towards electrocatalytic metallic impurities in nanocarbon materials.
CRGO-HU
CRGO-ST
CRGO-HU
CRGO-ST
B
-0.6
100
Potential (V)
Reduction Current (μA)
A
50
-0.7
-0.8
0
2
4
6
8
10
0
Number of cycles
2
4
6
Number of cycles
8
10
Figure 1 Variations of reduction current (A) and peak potential (B) of CHP with number of
cycles of purification in HNO3 of CRGO-HU (blue) and CRGO-ST (red). Error bars represent
triplicate measurements.
1
Stuart, E. J. E.; Pumera, M. J. Phys. Chem. C 2010, 114, 21296—21298.
224
F-44
Bilirubin oxidase from Myrothecium verrucaria physical adsorbed
on graphite electrodes. Insights into the alternative resting form of
the enzyme and the impact of chloride, temperature and pH
Federico Tasca1, Riccarda Antiochia2, Gabriele Favero2, Franco Mazzei2
1*
2
Facultad de Química y Biología, Departamento de Química de los Materiales, Universidad de Santiago de
Chile, Casilla 40, Correo 33, Sucursal Matucana, Santiago 9170022, Chile, ([email protected])
Department of Chemistry and Drug Technologies, Sapienza University of Rome, P.le A. Moro 5, 00185 Roma,
Italy
The oxygen reduction reaction (ORR) is one of the most important chemical processes in
energy converting systems and living organisms. Mediator-less, direct electro-catalytic
reduction of oxygen to water was obtained on spectrographite electrodes modified by physical
adsorption of bilirubin oxidases from Myrothecium verrucaria1. The existence of an
alternative resting form of the enzyme is validated2,3 and the effect of temperature, pH, and
chloride on the catalytic cycle are analyzed. Previous results on the electrochemistry of BOD
and on the impact of the presence of chloride are presented under new perspectives and new
interpretations are formulated.
[1] Bilirubin oxidases from Myrothecium verrucaria: insights into alternative resting form and the impact of
chloride, temperature and pH. Federico Tasca. Analytica Chimica Acta, Submitted.
[2] Spectroscopic and Crystallographic Characterization of ‘Alternative Resting’ and ‘Resting Oxidized’
Enzyme Forms of Bilirubin Oxidase: Implications for Activity and Electrochemical Behavior of Multicopper
Oxidases. Christian H. Kjaergaard, Fabien Durand, Federico Tasca, Munzarin F. Qayyum, Brice Kaufmann,
Sébastien Gounel, Emmanuel Suraniti, Keith O. Hodgson, Britt Hedman, Nicolas Mano, and Edward I.
Solomon. Journal of the American Chemical Society, 2012, 134 (12), 5548–5551.
[3] Copper Active Sites in Biology. Edward I. Solomon, David E. Heppner, Esther M. Johnston, Jake W.
Ginsbach, Jordi Cirera, Munzarin Qayyum, Matthew T. Kieber-Emmons, Christian H. Kjaergaard, Ryan G.
Hadt, and Li Tian. Chemical Reviews, 2014, pubs.acs.org/CR.
225
F-45
Impedance spectroscopic monitoring of the effect of phytochemical
compounds on wound healing in microfluidics
Valeria Tilli, Lucia Montini, Claudia Caviglia, Chen Bin, Marco Biagi, Daniela Giachetti,
Arto Heiskanen, Kinga Zór, Jenny Emnéus*
Section of Pharmaceutical Biology, University of Siena, Italy and Department of Micro- and Nanotechnology,
Technical University of Denmark, Denmark ([email protected])
*Department of Micro- and Nanotechnology, Technical University of Denmark, Denmark
Wound healing (WH) is a complex well-coordinated and regulated cascade of events taking
place without further complication in healthy individuals while abnormalities often occur in
patients with diabetes, severe infections or persons with vitamin or mineral deficiencies [1].
Phytochemical compounds (PCCs), plants and extract from plants, honey and bee propolis,
have been proved to have beneficial effect of WH processes [2,3]. Several PCCs has been
proved to have anti-inflammatory [4,5] and antioxidant [6,7] effect on WH. It has been shown
that medicinal plants induce activation of growth factors and extracellular matrix deposition
[8] as well as cells migration and proliferation [9]. However, there is a need for scientific
validation, standardization [10] and extensive studies for the understanding and elucidation of
the mechanism of action of PCCs.
To study complex biological problems such as WH and elucidate the effect of PCCs on this
process, thus finding new ways for treatment, there is a need for new technologies that enable
simultaneous multi-parameter detection. In this project we combine the advantages provided
by microfluidics cell culturing [11] and electrochemical detection [12]. Electrochemical
(bio)sensors have proven to be both sensitive and selective [13] and at the same time to enable
detection without destroying cellular integrity. Integration of electrode arrays with a
microfluidic cell culture device will allow dynamic real time monitoring of cell proliferation
and migration based on impedance spectroscopy [14-16] as well as intracellular redox status
using amperometric detection [17,18].
By measuring cell proliferation and changes in redox status of model cell lines (e.g.
fibroblast) during WH in wounds induced mechanically (Figure 1) of by UV, we are able to
learn more about the effect and role of PCCs on WH processes.
References:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Figure 1. Impedance tracking of wound ‘healing’
process during mechanically induced wound using
fibroblasts
226
13.
14.
15.
16.
17.
18.
Werner, S. and R. Grose, Phys. Rev., 2003. 83(3): p. 835-870.
Efem, S.E., Br. J. Surg., 1988. 75(7): p. 679-681.
Rawat, S., et al., Asian Pac J Trop Biomed., 2012. 2(3): p. S1910-S1917.
Borrelli, F., et al., Fitoterapia, 2002. 73(1).
Altavilla, D., et al., Pharmacology, 2008. 82(4): p. 250-256.
Sen, C.K., et al., Ann N Y Acad Sci., 2002. 957: p. 239-249.
Srinivas Reddy, B., et al., J Ethnopharmacol., 2008. 115(2): p. 249-256.
Zhang, Q., et al., Phytomedicine, 2013. 20(1): p. 9-16.
Fronza, M., et al., J Ethnopharmacol., 2009. 126(3): p. 463-467.
http://ec.europa.eu/health/human-use/herbal-medicines/.
Sabourin, D et al., J Lab Autom. 2013.18(3): p. 212-28
Vergani, M., et al., IEEE Trans Biomed Circuits Syst, 2012. 6(5): p. 498507.
Wang, J., Trends Anal. Chem, 2002. 21(4): p. 226-232.
Diemert, S., et al., J. Neurosci. Meth., 2012. 203: p. 69-77.
Caviglia C., et al.,. J. Phys.: Conf. Ser. , 2012. 407: p. 012029.
Shih, S.C.C., et al., Biosens Bioelectron, 2013. 42: p. 324-320.
Heiskanen, A., et al., Electrochem Commun, 2004. 6(2): p. 219-224.
Rahimi, M., et al., Anal. Bioanal. Chem., 201. 405(14): p. 4975-4979.
F-46
Determination of TBHQ in petroleum products using linear scan
voltammetry with a gold disc electrode
Tomášková Markéta, Chýlková Jaromíra
University of Pardubice, Faculty Chemical Technology, Institute of Environmental and Chemical Engineering,
Pardubice, Czech Republic ([email protected])
Typical petroleum products contain the additive compounds, such as detergents,
dispersants, corosion inhibitors and antioxidants. The quality of oil is negatively affected by
oxidation processes which are in relation with the presence of oxygen, higher temperatures
and pressures, as well as of catalytically acting agent [1]. First of all, the oxidation products
formed increase the acidity of oil, which results in its undesirable corrosive effects. The
pronounced oxidation may also increase the amount of carbon deposits and the viscosity of
oil, which deteriorates the resultant lubrication abilities. However, a proper addition of
antioxidants may significantly lower the degree of this unwanted oxidation, although the total
resistance against oxidation processes can not be achieved. After application of antioxidants
and their consumption, the oxidation as such is considerably accelerated and hence, the
especially, at elevated temperatures
belongs
evaluation of oxidation stability of oils
among the fundamental assays for the characterization of the oil quality [2].
For determination of antioxidant in biodiesel or oils, infrared spectroscopy [3] and
liquid chromatography [4] are often used, but both techniques are quite expensive or
demanding rather complicated sample preparation prior to analysis; in other words, they are
not suitable for field analysis. Electroanalytical methods represent a relatively cheap and
effective alternative with portable instrumentation with further possibility for miniaturization
[5-7].
In this work, a new method has been proposed for determination of TBHQ (tertbutylhydroquinone) in mineral oil and biodiesel when using linear-sweep voltammetry in
combination with a gold disc electrode. Samples of biodiesel were analyzed direct in
supporting electrolyte (isopropanol containing 0.1 mol L-1 H2SO4) without any special sample
treatment or separation. Samples of mineral oils had to be extracted with 96% ethanol [6].
The electroanalytical method developed has enabled the determination of TBHQ in real
biodiesel samples and spiked mineral oil samples with satisfactory results and prospects for
practical analysis.
References:
[1] R. M. Gresham, G. E. Totten. Lubrication and Maintenance of Indusrial Machinery.
USA: Florida; 2008.
[2] G. D. Hobson. Modern Petroleum Technology, 5th ed. Great Britain: Chichester; 1984.
[3] L. F. B. de Lira, M. S. de Albuquerque, J. G. A. Pacheco, T. M. Fonseca, E. H. D.
Cavalcanti, L. Stragevitch, M. F. Pimentel. Microchem. J. 96 (2010), 126.
[4] J. Y. Xin, H. Imahara, S. Saka. Fuel 88 (2009), 282.
[5] J. Chylkova, M. Tomaskova, T. Mikysek, R. Selesovska, J. Jehlicka. Electroanalysis 24
(2012), 1374.
[6] M. Tomaskova, J. Chylkova, O. Machalicky, R. Selesovska, T. Navratil. International
Journal of Electrochemical Science 8 (2013), 1664.
[7] M. Tomaskova, J. Chylkova, V. Jehlicka, T. Navratil, R. Selesovska. Scientific Papers
of the University of Pardubice, A 19 (2013), 155.
227
F-47
Biosensing of purine derivatives using a pencil graphite electrode
modified by copper: a promising tool in biomedicine
Libuse Trnkova, Rudolf Navratil, Vimal Sharma
Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, CZ-625 00 Brno, Czech
Republic
(*[email protected]; [email protected], [email protected])
Purine derivatives are important substances which can be found in blood, serum, urine and
other physiological liquids as products of human biochemical processes known under the term
purine catabolism. Here we suggest a simple, sensitive, easily accessible and very cheap tool
for their electrochemical analysis – a pencil graphite electrode (PeGE) modified by copper or
copper nanoparticles (AgCu). The modification of PeGE surface by monovalent copper ions
was performed by the reduction of Cu(II) from solution or by the oxidation of Cu(0) from
nanoparticles immobilized on the electrode surface. Purine derivatives react with Cu(I) to
form Cu(I)-purine complexes which remain for a certain time at the electrode surface. This
time is used for the linear sweep voltammetric (LSV) experiment in an adsorptive stripping
mode. The application of elimination voltammetry with linear scan (EVLS), which provides a
special signal for a totally adsorptive electroactive species, allows increasing substantially the
sensitivity evaluated by LOD from micromolar to units of nanomolar concentrations and
separating overlapped purine signals. Moreover, the sensing can employ not only oxidation
signals of purine derivatives but also oxidation signals of the corresponding copper
complexes. These complexes were identified by means of titration of electrochemically
produced cuprous ions by purine derivatives. The detection limits achieved by this approach
are three orders of magnitude lower than those found with UV absorbance detection. As the
detection does not require oxygen-free environment, our PeGE modified by monovalent
copper may serve as a suitable electrochemical sensor for purines also in biomedicine.
Acknowledgement
This research was supported by the CEITEC – Central European Institute of Technology
Project CZ. 1.05/1.1.00/02.0068, by the projects: Postdoc I, reg. No. CZ.1.07/2.3.00/30.0009,
MUNI/A/0972/2013, and LH 13053 KONTAKT II of the Ministry of Education, Youth and
Sports of the Czech Republic.
References
[1] H. Ashihara, H. Sano, A. Crozier, Phytochem. 2008, 69, 841-856.
[2] L. Trnkova in: V. Adam, R. Kizek (eds.), Utilizing of Bio-electrochemical Methods
in Biological Research, Research Signpost, Kerala, India, 2007, Ch. 4, p. 51-74 and
Ch. 8, p. 153-171.
[3] N. Aladag, L. Trnkova, A. Kourilova, et al., Electroanalysis, 2010, 22, 1675-1681.
[4] L. Trnkova, F. Jelen, M. Ozsoz, in: M. Ozsoz (ed.) Electrochemical DNA Biosensors,
2012, Ch.11, p. 355-378.
[5] R. Navratil, F. Jelen, Y.U. Kayran, L. Trnkova, Electroanalysis, 2014 (accepted).
228
F-48
New 1-vinyl-azulenyl molecular ligands for the detection of
lanthanide cations
Cristina-Andreea Amarandei, George-Octavian Buica, Eleonora-Mihaela Ungureanu and
Liviu Birzan*
Faculty of Applied Chemistry and Material Sciences, University "Politehnica" of Bucharest, 1-7 Gheorghe
Polizu, 011061, Bucharest, Romania ([email protected]),
* Romanian Academy, Organic Chemistry Center “C.D. Nenitzescu”, Splaiul Independentei 202B, 71141
Bucharest, Romania
Some new 1-vinyl-azulenes which are stabilized by electron withdrawing groups attached
to the vinyl group were prepared and characterized [1]. Those compounds could interact with
the metallic cations through the dicarbonyl moiety (Scheme 1, Table 1).
Scheme 1
Table 1.
R1
COOEt
COOEt
COMe COOEt COOEt COOEt CONH2
R2
COOH
COOEt
COMe
CN
COCF3
COMe
CONH2
Compound
a
b
c
d
e
f
g
CONHnBu
CONHnBu
h
CONHH
CH2CH2OH
CONHCH=C(COOEt)2
CH2CH2OH
i
j
The electrochemical behaviour of these new azulenic derivatives was studied by
electrochemical methods (cyclic and differential pulse voltammetry, rotating disk electrode)
on glassy carbon electrode [2]. The recognition of the lanthanide cations was performed in
organic (acetonitrile) or aqueous (acetate buffer) medium. The redox processes evidenced by
cyclic voltammetry and differential pulse voltammetry were established, analyzed and
assessed to the particular functional groups at which they take place. The complexation
behavior towards lanthanide metal ions (Sm3+, Eu3+, Yb3+, Tb3+) was studied by
electrochemistry and UV-Vis spectroscopy.
References
[1] C.-A. Amarandei, G. O.Buica, G. A. Inel, L. Birzan, E. M. Ungureanu, Acta Chimica Slovenica,
2014, in press.
[2] A. C. Razus, S. Nica, L. Cristian, M. Raicopol, L. Birzan, A. E. Dragu, Dyes Pigm., 2011, 91, 5561.
Acknowledgements: The authors gratefully acknowledge for the finacement to the Exploratory Research
Projects PN-II-ID-PCE-2011-3, project ID 15/2011.
229
F-49
Electrochemical Analysis of Proteins Using Ionic Liquids as
Solubilizers, Adsorption Solvents and Electrolytes
Jan Vacek, Jiri Vrba, Martina Zatloukalova and Martin Kubala*
Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry, 3DODFNê University,
Hnevotinska 3, 77515 Olomouc, Czech Republic, [email protected],
*
Department of Biophysics, Faculty of Science, Palacky University, 17. listopadu 12, 771 46 Olomouc,
Czech Republic
This study focuses on application of room temperature ionic liquids (RTILs) as solubilizers,
adsorption solvents and supporting electrolytes for electrochemical analysis of human and
bovine serum albumins, HSA and BSA (see Scheme). The proteins were analyzed by ex situ,
adsorptive transfer, square-wave voltammetry (SWV) at a basal-plane pyrolytic graphite
electrode after solubilization using imidazolium- and ammonium-based RTILs. The
application of RTILs enabled electrochemical scan from 0 to +1.5 V (vs. Ag/AgCl3 M KCl)
without interference with the anodic response of the proteins. Concretely, Tyr (Y) and Trp
(W) oxidation currents of HSA and BSA, peak Y&W around +0.85 V, were observed and
characterized under different RTILs andRTIL/water conditions.
The electrochemical data were supported by electrophoresis under denaturing and native
conditions. These provided evidence for the structural changes and stability of the studied
proteins in the presence of RTILs. The data acquired using BSA and HSA model proteins,
could be used in further applications of RTILs in protein electrochemistry and for developing
new protein sensing strategies.
Reference
[1] J. Vacek, et al., Electrochemical oxidation of proteins using ionic liquids as solubilizers,
adsorption solvents and electrolytes, Electrochim. Acta (in press), doi: 10.1016/
j.electacta.2013.06.115
This work was supported by the Ministry of Industry and Trade of the Czech Republic (FR-TI4/457).
230
F-50
Boron-doped diamond microelectrode arrays for electrochemical
monitoring of antibiotics contamination in water
Mikhail Yu. Vagin, Ingemar Lundstrom
Anthony P.F. Turner, Valerio Beni and Mats Eriksson
Department of Physics, Chemistry and Biology, Linköping University, 58183, Linköping, Sweden
([email protected])
The improvement of water management and increasing the access to safe drinking water can
develop the quality of life for millions of people world-wide and reduce child mortality due to
water-borne diseases [1]. Sweden was recently affected by the lack of appropriate water
management which resulted in microbial contamination and tens of thousands of people
falling ill [2]. Pollution with chemical compounds is also a waterworks concern. The
appearance of pharmaceuticals such as antibiotics in raw water affects the cleaning processes
at waterworks [3]. Substances which are not, or are only partly, eliminated in the sewage
treatment plant will reach the surface water where they may affect organisms of different
trophic levels and cause, for example, the of antibiotics resistance [4]. The inhibition of
bacteria of waste water plants by antibiotics may seriously affect organic matter degradation.
The efficiency of nitrification as an important step in waste water purification, can be
decreased by antibiotics inhibition [5].
Boron-doped diamond (BDD) is an advanced electrode material that possesses the
combination of good electrical conductivity achieved via film doping and the extreme
chemical inertness of diamond, which gives rise to a number of highly desirable properties of
BDD as electrode material: a wide potential window in aqueous media allows
electrochemical measurements at both extreme anodic and cathodic potentials, very low
capacitive currents leads to a sensitivity increase and extreme chemical and structural
inertness prevents electrode fouling [6].
Usage of a microelectrode array as the working electrode offers a variety of benefits for
electroanalysis: an improvement of the analytical performance in comparison with
macroelectrodes under planar diffusion, higher signal-to-noise ratios due to low capacitive
currents at the small surface area, shorter response times and less sensitivity to variations in
the water flow rate.
The BDD arrays of this work contain 2900 microelectrodes (10 µm diameter each) and have
been used for the detection of antibiotics (ofloxacine and canamycin A) in water with high
amplitude pulse voltammetry processed by multivariate data analysis. The detection limits
observed in monitoring mode were comparable with the characteristics of standard protocols
of antibiotics detection, which opens the possibility for continuous monitoring of water.
[1] The United Nations, World Water Development Report 4, 2012; [2] Lindberg, A. et al.,
FOI-R--3376--SE, 2011; Dryselius, R.; National Food Agency, Sweden, 2012; [3] Kummerer
K. Chemosphere, 2009, 75, 417; [4] Kummerer K. Chemosphere, 2009, 75, 435; [5]
Dokianakis, S.N. et al., Water Sci. Technol. 50, 341; [6] Goeting, C. et al.,
NewDiam.Front.C.Tech. 1999, 9, 207; Compton, R. et al., Electroanal. 2003, 15, 1349.
Acknowledgements: The Swedish research council Formas and the strategic research centre
Security Link for financial support.
231
F-51
Flow-through enzyme immobilized detector for the rapid
screening of acetylcholinesterase inhibitors
Cobra Parsajoo, Marie Vandeput, Jean-Michel Kauffmann
Laboratory of Instrumental Analysis and Bioelectrochemistry, Faculty of Pharmacy, Université Libre de
Bruxelles, Boulevard du Triomphe, Campus Plaine, CP 205/06, 1050, Brussels, Belgium, ([email protected]).
A commercially available thin-layer flow through amperometric detector, with the sensing
block customized in an original design, was applied for the screening of five drug compounds
known as acetylcholinesterase (AChE) inhibitors [1]. AChE from electric eel was covalently
immobilized by using the homobifunctional linker glutaraldehyde through a Schiff base
linkage onto a cysteamine modified gold disk adjacent to a silver disk working electrode. Online studies were performed by flow injection analysis (FI).
Operational stability and
parameters affecting the inhibitory potencies were studied; effect of incubation time, pH of
flow carrier, buffer concentration, flow rate and detector applied potential. The highest
inhibition percentage (I%) for Neostigmine as model drug was obtained in phosphate buffer
0.01 M, KCl 0.01 M, pH 8.00 at an applied potential of 0.08V vs. Ag/AgCl. Drug inhibition
screening, however, was realized using a PBS buffer of pH 7.4. Neostigmine, Eserine,
Tacrine, Donepezil and Galantamine were investigated by this set up and their IC50 compared.
The same trend of inhibitory potencies as described in the literature was found. In addition to
the IC50 of molecules of pharmacological interest this flow-through detector permitted to
determine the recovery rate of the inhibited enzyme.
[1] Parsajoo, C., Kauffmann, J-M. Development of an acetylcholinesterase immobilized flow
through amperometric detector based on thiocholine detection at a silver electrode. Talanta
109 (2013) 116-120.
232
F-52
Photo-electrochemical communication between Rhodobacter
capsulatus and electrode for harnessing solar energy
Kamrul Hasan*1, Kesava Vijalapuram Raghava Reddy, Kamil Górecki, Peter Ó Conghaile
Cecilia Hägerhäll, Dónal Leech, Lo Gorton
1
Department of Biochemistry and Structural Biology, Lund University, P.O. Box 124, SE-22100 Lund, Sweden
*[email protected]
Abstract
All forms of life require energy that originates from the sun via a naturally tuned process
called photosynthesis. Higher plants, algae and some photosynthetic bacteria convert solar
energy into organic chemical energy. Photo-microbial fuel cells can be exploited to meet the
growing demand for sustainable energy [1]. The metabolically versatile purple Rhodobacter
capsulatus is a potential candidate to study the electrogenic activity in the presence of light.
The use of flexible osmium redox polymers has gained attention for its efficient electron
transfer properties both with redox enzymes [2] and with bacterial cells [3, 4] and recently
heterotrophically grown R. capsulatus [5] wired with one of the osmium redox moieties.
In this communication, photo-heterotrophically grown R. capsulatus cells electrostatically
bound in the osmium polymer matrix demonstrated efficient electrical “wiring” with the
electrodes and were able to generate a significant current ≈10 µAcm-2 with malate/lactate as
substrate. The cells trapped in the polymer matrix were exited with visible light and the
subsequent photosynthetic electron transfer takes place onto the electrode recorded in both
chronoamperometric and cyclic voltammetric measurements. In addition to the photocurrent
generation, this study demonstrates the development of the possibility of other photobioelectrochemical devices based on R. capsulatus.
References
[1] M. Rosenbaum, Z. He, L.T. Angenent, Light energy to bioelectricity: photosynthetic microbial fuel
cells, Curr. Opin. Biotechnol., 21 (2010) 259-264.
[2] A. Heller, B. Feldman, Electrochemical Glucose Sensors and Their Application in Diabetes
Management, in: M. Schlesinger (Ed.) Applications of Electrochemistry in Medicine, Springer US,
2013, pp. 121-187.
[3] J. Du, C. Catania, G.C. Bazan, Modification of Abiotic-Biotic Interfaces with Small Molecules and
Nanomaterials for Improved Bioelectronics, Chemistry of Materials, 26 (2013) 686-697.
[4] K. Hasan, S.A. Patil, D. Leech, C. Hägerhäll, L. Gorton, Electrochemical communication between
microbial cells and electrodes via osmium redox systems, Biochemical Society Transactions, 40
(2012) 1330-1335.
[5] K. Hasan, S.A. Patil, K. Go'recki, D. Leech, C. Hägerhäll, L. Gorton, Electrochemical
communication between heterotrophically grown Rhodobacter capsulatus with electrodes mediated by
an osmium redox polymer, Bioelectrochemistry, 93 (2013) 30-36.
233
F-53
'HWHFWLRQDQGGLDJQRVLVRIYDULRXVFRQWDPLQDWLRQVLQHOHFWURSODWLQJ
EDWKE\DYROWDPPHWULFVHQVRUDFDVHVWXG\
.D]LPLHU]:LNLHO$OHNVDQGHU-DZRUVNL+DQQD:LNLHO
7HFKQLF,QF0ROWHU6W&UDQVWRQ5,86$
$GYDQFHGFRSSHUHOHFWURGHSRVLWLRQSURFHVVHVDUHURXWLQHO\XVHGE\WKHVHPLFRQGXFWRU
LQGXVWU\ IRU GDPDVFHQH DQG WKURXJKVLOLFRQ YLD 769 SURFHVVHV IRU WKH IDEULFDWLRQ RI XOWUD
ODUJH VFDOH LQWHJUDWHG FLUFXLWV 7KLV LQGXVWU\ ZKLFK LV DQ DYDQWJDUGH RI WHFKQRORJLFDO
GHYHORSPHQWKDVFKDOOHQJLQJDQGVWULQJHQWPDQXIDFWXULQJVSHFLILFDWLRQV$VDFRQVHTXHQFH
FRQYHQWLRQDO XQLYDULDWH SURFHVV FRQWURO PHWKRGV QHHG WR EH UHSODFHG E\ FKHPRPHWULF
WHFKQLTXHV ZKLFK XWLOL]H HYHULQFUHDVLQJ PXOWLYDULDWH GDWD PRUH WKRURXJKO\ DQG HIILFLHQWO\
7KH DSSOLFDWLRQV RI FKHPRPHWULFV FDQ EH URXJKO\ GLYLGHG EHWZHHQ WKRVH GLUHFWHG DW
PDLQWHQDQFH RI SURFHVV LQVWUXPHQWV FDOLEUDWLRQ DQG WKRVH WKDW DUH FRQFHUQHG ZLWK
PDLQWHQDQFHRIWKHSURFHVVLWVHOIIDXOWGHWHFWLRQ7KHIRFXVRIWKLVSUHVHQWDWLRQLVSXWRQWKH
ODWWHU$TXLFNRQOLQHGLDJQRVLVRIGLVWXUEDQFHVWKDWOHDGWRRXWRIFRQWUROSURFHVVEHKDYLRU
LVFULWLFDOIRUUHGXFLQJORVVHVLQSURFHVVRSHUDWLRQV
$QLQVLWXVHQVRUHPSOR\LQJ'&DQG$&YROWDPPHWU\WHFKQLTXHVZDVGHVLJQHG>@WR
SURYLGH D UHVSRQVHVWURQJO\ DIIHFWHG E\ VSHFLILFSHUWXUEDWLRQVOLNHO\ WR RFFXU LQWKH UHDOOLIH
FRQGLWLRQV VXFK DV DFFXPXODWHG GHJUDGDWLRQ SURGXFWV VHYHUHO\ RXWRIWDUJHW FRQFHQWUDWLRQV
RI EDWK FRQVWLWXHQWV DQG RXWRIWDUJHW SK\VLFDO FRQGLWLRQV RI WKH SODWLQJ SURFHVV LH
WHPSHUDWXUH
6RIW ,QGHSHQGHQW 0RGHOOLQJ RI &ODVV $QDORJ\ 6,0&$ LV D SDWWHUQ UHFRJQLWLRQ
PHWKRG WKDW GHVFULEHV HDFK FODVV VHSDUDWHO\ LQ HLJHQYHFWRU VSDFH >@ ,Q WKLV VXSHUYLVHG
FODVVLILFDWLRQWHFKQLTXHWKHSURMHFWHGQHZPHDVXUHPHQWVDUHHYDOXDWHGWRGHWHUPLQHZKHWKHU
WKH\EHORQJWRDFHUWDLQFODVVRUQRW
7KLV SUHVHQWDWLRQ GHVFULEHV DFWXDO LQGXVWULDO FDVHV HQFRXQWHUHG GXULQJ VHPLFRQGXFWRU
PDQXIDFWXULQJ WKDW ZHUH UHVROYHG ZLWK WKH DXWRPDWHG DQDO\WLFDO V\VWHP >@ FDSDEOH RI
FROOHFWLQJ RQOLQH YROWDPPHWULF GDWD DQG LQYHVWLJDWLQJ VLPLODULWLHV EHWZHHQ PHDVXUHPHQWV LQ
SURSHU FRQGLWLRQV DQG PHDVXUHPHQWV ZLWK XSVHW EHKDYLRU 7KH VKDSH GLIIHUHQFHV EHWZHHQ
GHIRUPHG DQG UHIHUHQFH VHW YROWDPPRJUDPV DUH TXDQWLILHG E\ 0DKDODQRELV 'LVWDQFH 0'
6,0&$>@
6SHFLILFDOO\ WKH HIIHFWLYHQHVV RI WKH V\VWHP ZDV SURYHQ LQ WZR UHDOOLIH FDVHV RI
GHWHFWLRQRIIRUHLJQFRQWDPLQDWLRQLQDFRSSHUGDPDVFHQHEDWK
ZLWKK\GURJHQSHUR[LGHFDXVHGE\DOHDNLQWRWKHSODWLQJUHVHUYRLUWDQNIURPDIDXOW\
V\ULQJHGXULQJSURGXFWLRQDQG
ZLWK LURQ FDXVHG E\ WKH XQQRWLFHG GURSSLQJ RI D FDUERQVWHHO FKDSPDQ ELW LQWR WKH
SODWLQJFKDPEHUZKLOHFKDQJLQJWKHDQRGHEHWZHHQKLJKYROXPHSURGXFWLRQUXQV
7KDQNVWRWKHSURPSWZDUQLQJVLJQLILFDQWSURGXFWLRQORVVHVZHUHSUHYHQWHG
7KLV SUHVHQWDWLRQ DOVR IRFXVHV RQ D UHWURVSHFWLYH VWXG\ XWLOL]LQJ FKHPRPHWULF
FODVVLILFDWLRQ DQDO\VLV OHDGLQJ WR WKH GHYHORSPHQW DQG WUDLQLQJ RI D FRQVROLGDWHG DQDO\WLFDO
PRGHO FDSDEOH QRW RQO\ RI GHWHFWLRQ EXW DOVR RI GLDJQRVLV RI WKHVH VSHFLILF W\SHV RI
FRQWDPLQDWLRQE\XVLQJ ERWKDQXPHULFDODSSURDFKDQGDJUDSKLFDOSURMHFWLRQOHDGLQJWRWKH
DXWRPDWLRQRIDWURXEOHVKRRWLQJSURFHVV
5HIHUHQFHV
>@$-DZRUVNL+:LNLHO.:LNLHO(OHFWURDQDO\VLV1R >@5'H0DHVVFKDOFN$&DQGROIL'/0DVVDUW6+HXHUGLQJ&KHPRPHWULFV,QWHOO/DE6\VW
234
F-54
Voltammetric Behavior of Ampicillin and Penicillin G: Hanging
Mercury Drop Electrode (HMDE) VS Mercury Meniscus
Modified Silver Amalgam Electrode (m-AgSAE)
Mohd Dzul Hakim Wirzala, Abdull Rahim Mohd Yusoffb, Jiri Zimac and Jiri Barekc
a
b
Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, Malaysia
([email protected])
Institute of Environmental & Water Resource Management (IPASA), Universiti Teknologi Malaysia, Malaysia
c
Charles University in Prague, Faculty of Science, University Research Center UNCE “Supramolecular
Chemistry”, Department of Analytical Chemistry, UNESCO Laboratory of Environmental Electrochemistry,
Albertov 6, CZ-128 Prague 2,Czech Republic
In recent years, there has been an increasing concern about the presence of new emerging
pollutants such as pesticides, drugs and endocrine disrupting chemicals (EDC) in the aquatic
environment which can have huge effect on human health. The presences of pharmaceutical
compounds such as antibiotics have been observed in the water cycle including surface water,
ground water, sewage water, and even in drinking water. The objective of this research is to
study and compare the electrochemical properties of ampicillin and penicillin G at different
working electrodes, namely hanging mercury drop electrode (HMDE) and mercury meniscus
modified silver solid amalgam electrode (m-AgSAE) using differential pulse adsorptive
stripping voltammetry (DPAdSV). At HMDE, in Britton Robinson buffer (BRB, 0.04 M)
ampicillin and penicillin G showed a well-developed peak at -0.25 V at pH 7 and at -0.5 V at
pH 12, respectively. The following optimum conditions for its analytical use were found:
accumulation potential (Eacc) of 0 V, accumulation time (tacc) of 30 second, scan rate, 0.02 V/s
with pulse amplitude 0.050 V. At m-AgSAE, the DPV peak currents of ampicillin and
penicillin G had been observed at potential -0.2 V at pH 8 and -0.25 V at pH 12, respectively.
Ampicillin and penicillin G showed a linear response for DPAdSV in the concentration range
(1 - 5) × 10-8 mol/L with detection limit of 1.7 × 10-9 mol/L (HMDE) and 2.3 × 10- 8M (mAgSAE) for ampicilin and 2.3× 10- 9 M (HMDE) and 3.5 × 10- 8 M (m-AgSAE) for penicillin
G.
Keywords: Ampicillin, Penicillin G, Hanging Mercury Drop Electrode (HMDE), Mercury
Meniscus Silver Amalgam Electrode (m-AgSAE).
Acknowledgement
Financial support from the Grant Agency of the Czech Republic (project P206/12/G151) is gratefully
acknowledged.
235
F-55
Large-surface carbon film electrode – A beneficial sensor for
voltammetric determination of electrochemically oxidizable
organic compounds
Vlastimil Vyskoþil and Hana Šmejkalová
Charles University in Prague, Faculty of Science, University Research Centre UNCE "Supramolecular
Chemistry", Department of Analytical Chemistry, UNESCO Laboratory of Environmental Electrochemistry,
Hlavova 2030/8, CZ-12843 Prague 2, Czech Republic ([email protected])
A newly developed large-surface carbon film electrode (LS-CFE) [1] based on a microcrystalline
natural graphite–polystyrene composite film [2] was used to study the electrochemical
behavior of 4-nitrophenol (4-NP) using DC voltammetry (DCV) and differential pulse
voltammetry (DPV). The LS-CFE represents a very promising alternative to electrode
surfaces modified by carbon nanoparticles with profitable electrocatalytic properties (e.g.,
nanotubes or graphene) [2]. Recently, it has also been shown that the LS-CFE is a suitable
transducer for the preparation of electrochemical DNA biosensors [3].
Voltammetic behavior of 4-NP was investigated in dependence on the pH of the used BrittonRobinson buffer. As optimum pH values for the voltammetric determination of 4-NP at the
LS-CFE in the anodic potential region, the pH values 3.0 (for DCV) and 7.0 (for DPV) were
chosen. During the anodic oxidation of 1×10–4 mol L–1 4-NP, the passivation of the LS-CFE
surface occurred. Therefore, series of ten measurements were carried out always at a new carbon
film, and the determinations showed a good repeatability for both voltammetric techniques
used (RSD 3.7 % for DCV and 3.6 % for DPV). Under optimum conditions, the calibration
dependences of 4-NP were measured in the concentration range from 1 to 100 ȝmol L–1, with
the limits of quantification (LQs) of 1.5 ȝmol L–1 and 0.46 ȝmol L–1 for DCV and DPV,
respectively.
The applicability of the newly developed methods for the determination of 4-NP was verified
on model water samples. The LQs reached in the model samples of drinking and river water,
respectively, were 1.6 and 1.7 ȝmol L–1 for DCV and 0.46 and 0.60 ȝmol L–1 for DPV. Thus,
it can be concluded that the LS-CFE can be successfully used for the determination of trace
amounts of 4-NP and possibly of other electrochemically oxidizable organic compounds.
Financial support from the Grant Agency of the Czech Republic (Project GP13-23337P) is
gratefully acknowledged.
References
[1] H. Smejkalova, V. Vyskocil, Chem. Listy 2014, 108, 264.
[2] A. R. Khaskheli, J. Fischer, J. Barek, V. Vyskocil, Sirajuddin, M. I. Bhanger, Electrochim.
Acta 2013, 101, 238.
[3] V. Vyskocil, J. Barek, Procedia Chem. 2012, 6, 52.
236
F-56
Multiplexed determination of human growth hormone and
prolactin at a label free electrochemical immunosensor
using dual carbon nanotubes-screen printed electrodes
modified with gold and PEDOT nanoparticles
Paloma Yáñez-Sedeño, V. Serafín, G. Martínez-García, L. Agüí, J.M. Pingarrón
Department of Analytical Chemistry, Faculty of Chemistry, University Complutense of Madrid, 28040-Madrid
(Spain) ([email protected])
Human growth hormone (hGH) and prolactin (PRL) are naturally occurring peptide hormones
produced by the anterior pituitary gland. hGH is essential for body growth since it stimulates
the production of insulin growth factor (IGF-1), which in turn stimulates the production of
cartilage cells, resulting in bone growth. Also, hGH plays important roles in the metabolism
of proteins, lipids and carbohydrates. Prolactin (PRL) is involved in various important
biological processes such as stimulation of lactation, regulatory roles in the growth and
differentiation of the mammary glands, and in reproduction. Alterations in hGH and/or PRL
secretion are associated with health disorders frequently related to the existence of pituitary
adenomas. Much attention has been paid on hGH/PRL circulating levels in relation to
mammary tumour.
A label-free dual electrochemical immunosensor was constructed for the multiplexed
determination of human growth (hGH) and prolactin (PRL) hormones. The immunosensor
used an electrochemical platform composed of carbon nanotubes-screen printed carbon
electrodes (CNTs/SPCEs) modified with poly(ethylene-dioxythiophene) (PEDOT) and gold
nanoparticles, on which the corresponding hGH and PRL antibodies were immobilized. The
affinity reactions were monitored by measuring the decrease in the differential pulse
voltammetric oxidation response of the redox probe dopamine.The experimental variables
involved in the preparation of both AuNPs/PEDOT/CNTs/SPCE modified electrodes and the
dual immunosensor were optimized. The immunosensor exhibited an improved analytical
performance for hGH and PRL with respect to other electrochemical immunosensor designs,
showing wide ranges of linearity and low detection limits of 4.4 and 0.22 pg/mL, respectively.
An excellent selectivity against other hormones and in the presence of ascorbic and uric acids
was found. The usefulness of the dual immunosensor for the simultaneous analysis of hGH
and PRL was demonstrated by analyzing human serum and saliva samples spiked with the
hormones at different concentration levels, with mean recoveries near 100% in all cases.
.
237
F-57
Selective label free electrochemical impedance measurements of
glycated haemoglobin on 3-aminophenylboronic acid-modified
eggshell membranes
Yuwadee Boonyasit a , Orawan Chailapakul b,c and Wanida Laiwattanapaisald*
a
Graduate Program in Clinical Biochemistry and Molecular Medicine, Faculty of Allied Health Sciences,
Chulalongkorn University, Bangkok, 10330, Thailand
Electrochemistry and Optical Spectroscopy Research Unit, Department of Chemistry, Faculty of Science,
Chulalongkorn University, Bangkok, 10330, Thailand
c
National Center of Excellence for Petroleum, Petrochemicals, and Advanced Materials, Chulalongkorn
University, Bangkok, 10330, Thailand
*d
Department of Clinical Chemistry, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok,
10330, Thailand
E-mail: [email protected], [email protected]
b
An alternative approach to determine glycated haemoglobin (HbA1c) is proposed
using an effective cis-diols binding interaction. Selective sensing between non-glycated
haemoglobin (Hb) and HbA1c is obtained due to the unique feature of a new boronatemodified eggshell membrane. Label-free electrochemical impedance measurements were
employed with the eggshell membrane immobilized on top of a Dropsens platinum screenprinted electrode.
For construction of the boronate-modified eggshell membrane, a drop of 25% of
glutaraldehyde solution was placed on the surface of the membrane, and then thoroughly
washed with 0.01 M of 4-ethylmorpholine buffer (pH 8.5) before addition of 0.25 mg mL-1 of
3-aminophenylboronic acid. The excess aldehyde groups were subsequently removed by
rinsing with 0.01 M of ethanolamine buffer (pH 8.5) before washing again. Finally, various
concentrations of HbA1c were used to investigate whether the HbA1c could bind to the
selective sensing interface via cis-diols interaction. Each consecutive step was carried out on
the same piece of platinum screen-printed electrode with the use of a 5 mM Fe(CN)63-/4solution. EIS measurement was conducted over the frequency range 10 Hz to 100 kHz with an
applied potential at 0.134V. The results demonstrated in a step-wise manner that the boronatemodified eggshell membrane was highly responsive to a wide range of HbA1c levels (r2 =
0.972). Additionally, Fourier transform infrared (FT-IR) absorption spectroscopy was utilized
to verify the surface modification, indicating that the boronate-modified eggshell membrane
had the distinctive characteristics of surface functionalization. The proposed system has the
potential for continuously monitoring glycaemic levels in diabetic patients.
238
F-58
Blood-Gas Analyzer with Solid State Sensors
Birgit Zachau-Christiansen and Lars Juel Christensen
Radiometer Medical ApS, Åkandevej 21, DK-2700 Brønshøj, Denmark
([email protected])
On modern hospitals and especially at Intensive Care Units (ICU) there is an increasing
demand for blood gas analyzers that are simpler, faster, better. The analyzers are
preferentially placed at the “Point of Care” i.e. near the bed of patient on the ICU.
“Blood Gas” is short for measuring the respiratory parameters pO2, pCO2 and pH, while
measurement of cNa+, cK+, cCa2+, and cCl- monitors the electrolyte balance. Finally cLac and
cGlu reports on the metabolic status of the patient.
ABL90 – Flex meets these requirements by introducing miniaturized sensors comprised of
thick-film, screen-printed, solid state sensors all combined on a ceramic alumina substrate.
The analyzer contains mostly electrochemical sensors, but also some optical sensors are
included. The electrochemical sensors are ion-selective electrodes for pH, cNa+, cK+, cCa2+,
and cCl-. The pCO2 sensor is a Severinghaus type based on measuring the pH-change in an
HCO3- -electrolyte after the CO2 has diffused through a silicone membrane. The metabolite
sensors are conventional biosensors measuring the current used for oxidation of H2O2 after
reaction of the substrate and oxygen – catalyzed by lactate and glucose oxidase, respectively.
Oxygen (pO2) and the hemoglobin derivatives are all measured optically.
The simplicity is implemented by allowing only 2 consumables for operating the instrument.
These are the Sensor Cassette and the Solution Pack.
The Solution Pack contains calibrating solutions, quality control solutions and rinse-solutions.
The faster performance has been the largest challenge. The first step is implementation of a
compact flow channel allowing the measurement of 17 parameters in a very small sample
volume (65 μl). Further introduction of a one-point calibration to be taken just before the
sample has been introduced – the back-log signal treatment – has allowed a very short
analysis time of 35 s. In this context it has not been trivial to ensure that the one-point
calibration solution maintains all concentration values in the time from one sample
introduction/calibration to the next. This means that the concentration of the calibrant shall
remain constant during up to 4 h and the sensors have to be regenerated within the cycle time
of 60 s. Furthermore it is necessary that the temperature equilibration of the sample is fast
(<5s) and the sensors are fast enough to allow measurement within 17 s after aspiration.
In this compact instrument the measuring performance is comparable to the specifications of
our traditional bench top analyzers, e.g. ABL 800 – or better.
239
F-59
Boron Doped Diamond Electrodes: Influence of Boron Doping
Level on Potential Window and Determination of Oxidizable
Organic Compounds
Jaroslava Zavazalova, Jana Vosahlova, Petr Hammer, and Karolina Peckova
Charles University in Prague, Faculty of Science, University Research Centre UNCE "Supramolecular
Chemistry", Department of Analytical Chemistry, UNESCO Laboratory of Environmental Electrochemistry,
Albertov 6, CZ-128 43, Prague 2, Czech Republic ([email protected])
In electroanalysis, boron doped diamond (BDD) films have become popular as electrode
material because of combination of attractive electrochemical, physical, and mechanical
properties [1]. These properties, including morphology and microstructure, content of sp2
impurities, conductivity, corrosion resistance, and other characteristics, are among other
factors significantly influenced by boron concentration in BDD films [2]. Depending on the
boron-doping level and crystallinity of the BDD, the electrical conductivity of the BDD films
ranges from insulating to metallic with the predicted threshold for the
semiconductive/metallic transition at ~1020 boron atoms per cm −3 [3]. Until now, limited
attention has been paid to evaluation of the influence of boron-doping level on the
performance of the BDD in electroanalysis of organic compounds.
Thus, in this contribution we investigated for a set of oxygen-terminated BDD electrodes with
semimetallic or metallic conductivity the effect of base electrolyte composition on potential
window and voltammetric determination of oxidizable organic compounds. For this purpose,
a series of five BDD thin films were deposited by microwave plasma-assisted chemical vapor
deposition on silicon wafers of mixtures containing 99.0% H2/1.0% CH4 and trimethylboron
gas with variable B/C ratio in the gas phase 500, 1000, 2000, 4000, and 8000 ppm.
Commonly used buffers (acetate, phosphate, borate) and supporting electrolytes (KCl,
Na2SO4, HClO4) covering wide range of pH values as well as different ratio aqueous/organic
phase (e.g., acetonitrile and methanol) were used. In general, decreasing widths of potential
window, more pronounced at the cathodic side with increasing boron-doping level, was
obtained. The presence of methanol limits significantly the potential window in the anodic
region.
Further, the electroanalytical characteristics for model oxidizable organic compounds
(e.g., 2-aminobiphenyl, benzophenone-3) including peak potential, current density,
sensitivity, limit of detection etc. will be assessed for batch voltammetric methods.
This research was carried out within the framework of Specific University Research
(SVV260084). The research was financially supported by the Grant Agency of Charles
University in Prague (Project GAUK 684213).
[1] Peckova K., Musilova J., Barek J.: Crit. Rev. Anal. Chem. 39 (2009) 148.
[2] Vlckova-Zivcova Z., Frank O., Petrak V., Tarabkova H., Vacik J., Nesladek M., Kavan L.:
Electrochim. Acta 87 (2013) 518.
[3] Williams A. W. S., Lightowlers E. C., Collins A. T.: J. Phys. C: Solid State Phys. 3 (1970)
1727.
240
F-60
Human sulfite oxidase on semiconductive nanoparticles with
efficient bioelectrocatalysis
T.Zenga, S.Frascaa, O.Rojasb, K. Lemkeb, J. Koetzb, S. Leimkühlera, U. Wollenbergera
(a) Institute of Biochemistry and Biology and (b) Institute of Chemistry
University Potsdam, 14476 Potsdam/Golm, Germany
[email protected]
Metal and semiconductor nanoparticles can act as functional units for electro
analytical applications especially electrochemical sensors and biosensors due to their
unique chemical and physical properties[1]. In our work, human sulfite oxidase (hSO),
a heme- and molybdo- cofactor containing redox enzyme which can catalyze the
oxidation of sulfite to sulfate, was successfully immobilized on a gold nanoparticle
modified electrode[2]. Here we have applied poly(ethyleneimin)-entrapped
semiconductive CdS nanoparticles[3] and shown that the efficiency of direct electron
transfer between hSO and electrodes and electrocatalytic sulfite oxidation is further
improved. Variations of the buffer solution conditions, e.g. ionic strength, pH,
viscosity and effect of oxygen were studied in order to understand intramolecular and
heterogeneous electron transfer from Moco via Cytb5 to the electrode. The results are
consistent with a model derived for the enzyme in solution studied by using flash
photolysis[4] and molecular dynamic simulations from SERR spectroelectrochemistry
of hSO on monolayer modified electrodes[5]. Applications of this sensor approach will
be discussed.
[1] X. Luo, A. Morrin, A. J. Killard and M. R. Smyth, Electroanalysis 2006, 18, 319-326.
[2] S. Frasca, O. Rojas, J. Salewski, B. Neumann, K. Stiba, I. M. Weidinger, B. Tiersch, S.
Leimkuhler, J. Koetz and U. Wollenberger, Bioelectrochemistry 2012, 87, 33-41.
[3] S. Kosmella, J. Venus, J. Hahn, C. Prietzel and J. Koetz, Chemical Physics Letters 2014,
592, 114-119.
[4] C. Feng, R. V. Kedia, J. T. Hazzard, J. K. Hurley, G. Tollin and J. H. Enemark,
Biochemistry 2002, 41, 5816-5821.
[5] M. Sezer, R. Spricigo, T. Utesch, D. Millo, S. Leimkuehler, M. A. Mroginski, U.
Wollenberger, P. Hildebrandt and I. M. Weidinger, Phys Chem Chem Phys 2010, 12,
7894-7903.
241
F-61
Multiple pulse galvanostatic preparation of bismuth particle
electrode for trace toxic element detection
Tanja Zidaric, Vasko Jovanovski, Samo Hocevar
Analytical Chemistry Laboratory, National Institute of Chemistry, Hajdrihova 19, SI-1001, Ljubljana, Slovenia
([email protected])
Electrodeposition of bismuth particles on a glassy-carbon electrode by means of multiple
pulse galvanostatic polarization represents an alternative way to prepare ex situ formed
bismuth particle electrode (BiPE) for trace toxic element detection. The multiple pulse
galvanostatic pre-plating of bismuth particles onto a glassy carbon supporting electrode was
investigated and optimised with aim of achieving improved electroanalytical performance of
BiPE, e.g. low limits of detection, compared to those observed at conventional ex situ and in
situ prepared BiFEs, while maintaining favourable electrochemical and mechanical stability
of the bismuth modification. The influence of several key variables of bismuth particle
preparation, such as plating solution, current and duration of pulses, were studied with respect
to the signals of anodic stripping voltammetric measurements of trace cadmium(II) and
lead(II) as model analytes. The BiPE was prepared ex situ on a glassy-carbon electrode from
0.1 M acetate buffer solution (pH 4.5) containing 20 mg/l of bismuth(III) together with 40
mg/l of NaBr (auxiliary ligand). After optimisation, the resulting BiFE exhibited well-defined
stripping peaks along with a low background contribution. In combination with square-wave
anodic stripping voltammetry highly linear behaviour was obtained in the examined low
concentration range of 1 μg/l to 10 μg/l, with excellent limits of detection, i.e. 0.7 μg/l for
cadmium(II) and 0.07 μg/l for lead(II) associated with 5 minutes accumulation, and good
repeatability with the RSD of 1.96 % for 1 μg/l lead(II). Evidently, the proposed multiple
pulse galvanostatic preparation protocol resulted in BiPE with enhanced electroanalytical
performance which surpasses those of conventionally prepared in situ and ex situ BiFEs.
Fig. 1: Stripping voltammograms of cadmium and lead at glassy-carbon electrode coated with bismuth film
(dash line) and bismuth particles (solid line). Measurement solutions, containing 0.05 M acetate buffer (pH 4.5)
with 5 μg/l cadmium(II) and lead(II); accumulation potential and time: -1.2V and 120 s.
242
F-62
Carbon Paste and Fibre Rod Electrodes in Determination of
Biologically Active Organic Compounds
Jiri Zima, Hana Dejmkova
Charles University in Prague, Faculty of Science, University Research Centre “Supramolecular chemistry”,
Department of Analytical Chemistry, UNESCO Laboratory of Environmental Electrochemistry, Albertov 6, CZ128 43 Prague 2, Czech Republic ([email protected])
Abstract: In this contribution, new voltammetric and amperometric methods for
determination of selected biologically active compounds are described employing either
various types of carbon paste electrodes (CPE), or composite fibre rod electrode (CFRE)
using differential pulse voltammetry (DPV), direct current voltammetry (DCV), and cyclic
voltammetry (CV) in batch arrangement and HPLC with electrochemical detection (HPLCED). The results of determination of cymoxanil, and famoxadone [1], 2,4dihydroxybenzophenone [2], 2-hydroxy-4-methoxybenzophenone [2,3], chlortoluron [4],
carboxin [5], triclosan [6], diafenthiuron [7], and propyl gallate [8] will be compared and
discussed. Glassy carbon spherical microparticles were used as carbonaceous component of
the paste. The limits of detection of some analytes were below 1•10-7 mol l-1 in both batch and
flow methods. The newly developed methods of determination were applied to model samples
of drinking and river water, soils, and practical samples of edible oil, toothpaste, soap, and
toilet water.
Keywords: Carbon paste electrodes; Composite fibre rod electrode; Glassy carbon spherical
microparticles; HPLC-ED; Differential pulse voltammetry; Biologically active organic
compounds
Acknowledgement: Financial support from the Grant Agency of the Czech Republic (project
P206/12/G151) is gratefully acknowledged.
References:
1. D. Bavol, Master Thesis, Charles University in Prague, 2013.
2. B. Fähnrichova, Master Thesis, Charles University in Prague, 2013.
3. V. Molitor, Bachelor Thesis, Charles University in Prague, 2013.
4. L. Houskova, Master Thesis, Charles University in Prague, 2012.
5. R. Jarosova, Master Thesis, Charles University in Prague, 2013.
6. P. Mala, Bachelor Thesis, Charles University in Prague, 2012.
7. J. Markvart, Bachelor Thesis, Charles University in Prague, 2013.
8. M. Vysoka, Master Thesis, Charles University in Prague, 2010.
243
F-63
Towards direct voltammetric determination of Ascorbic acid in
natural pepper fruits without sample treatment
Zsuzsanna Őri, Lívia Nagy, Géza Nagy*
University of Pécs, Department of General and Physical Chemistry, 7624 Pécs Ifjúság Str. 6., Hungary
([email protected])
* University of Pécs, Department of General and Physical Chemistry, 7624 Pécs Ifjúság Str. 6., Hungary
([email protected])
In voltammetric analysis the current resulted by electrode reaction of the analyte
is used for evaluation. In optimal cases the current is determined by the diffusion mass
transport of the electroactive analyte. Well known basic equations relating to different
voltammetric methods show that well defined linear dependence exists between the
current and the analyte concentration. Therefore calibration curves are used for
evaluating the concentration of sample solutions. Evaluation with the calibration data
can result in accurate concentration value as long as the diffusion coefficient of the
detected species is the same in the standard and in the sample solution. However, if it is
not the case, then the calibrating data obtained with the standard solution can not be
used for obtaining reliable concentration values. In our recent studies a way for solving
those special analytical tasks with voltammetric technique has been worked out. The
method employs short time chronoamperometric data collection and a thin diffusion
layer coated working electrode. Doing the measurements the built in diffusion layer at
the electrode surface is equilibrated with the sample or with the standard solutions.
Appropriate constant measuring potential is selected. As the electrode reaction
proceeds, the concentration of the detected species decreases in the vicinity of the
electrode. Short time after the electrolysis started the diffusion profile is inside the built
in diffusion layer. Therefore we can use the short time current values recorded in
aqueous calibrating standards for evaluating short time chronoamps recorded in special
standards.
Ascorbic acid (AA) can be found in many biological systems, namely in fresh
vegetables and fruits, as the most ubiquitous water-soluble vitamin ever discovered.
Nowadays, High Performance Liquid Chromatography (HPLC) methods are the most
frequently used analytical techniques for the determination of AA. However they are
quite expensive methods, extraction, and sample preparation procedures are required.
In our work the applicability of the built in diffusion layer modified electrode and
chronoamperometric method was investigated in determination of AA concentration of
the tortuous media of different raw vegetables like yellow pepper. The poster will
summarise our most recent results. Interestingly significant differences were obtained in
AA concentration of surface layer cut by ceramic knife and stainless steel. The applied
membrane successfully reduced the undesirable electrode fouling caused by the
secondary metabolites (carotenoids, flavonoids, etc.).
Acknowledgements: This research was supported by the Richter Gedeon Talentum
Foundation and by the Hungarian research project No. TÁMOP-4.2.2.A-11/1/KONV-2012006
244