Atomic spectrometry update. Clinical and biological materials, foods and beverages

Transcription

ASU REVIEW
Andrew Taylor,*a Simon Branch,b David Halls,c Marina Patriarcad and Mark Whitee
www.rsc.org/jaas
Atomic spectrometry update. Clinical and biological materials,
foods and beverages
a
Supra-regional Assay Service, Trace Element Laboratory, Centre for Clinical Science and
Measurement, School of Biomedical and Life Sciences, University of Surrey, Guildford,
Surrey, UK GU2 7XH. E-mail: [email protected]
b
The Lord Rank Centre, R. H. M. Technology, Lincoln Road, High Wycombe,
Buckinghamshire, UK HP12 3QR
c
1A Bloomfield Road, Lesmahagow, Lanark, UK M11 0DF
d
Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Roma, Italy
e
Health and Safety Laboratory, Health and Safety Executive, Broad Lane, Sheffield
UK S3 7HQ
Received 10th February 2005
First published as an Advance Article on the web 3rd March 2005
1
1.1
1.2
1.2.1
1.2.2
1.2.3
1.3
1.3.1
1.3.2
1.3.2.1
1.3.2.2
1.3.2.3
1.3.2.4
1.3.2.5
1.3.3
1.3.3.1
1.3.3.2
1.3.3.3
1.3.3.4
1.3.3.5
1.3.4
DOI: 10.1039/b501936b
1.4
1.5
1.6
1.7
1.7.1
1.7.2
1.7.3
1.7.4
1.7.5
1.7.6
1.7.7
1.7.8
1.7.9
1.7.10
1.7.11
1.7.12
1.7.13
1.7.14
Analysis of clinical and biological materials
General reviews and articles
Sampling and sample preparation
Sample digestion
Solid sampling
Sample preconcentration
Developments in and applications of multi-element
techniques
Atomic emission spectrometry with the inductively
coupled plasma or microwave induced plasma
Inductively coupled plasma mass spectrometry and
other mass spectrometric techniques
Reviews
Multielement determination by ICP-MS
Laser ablation ICP-MS
Secondary ion mass spectrometry
Accelerator mass spectrometry
X-ray fluorescence spectrometry
Reviews
Elemental mapping
Developments in in vivo XRF determination
Determination of elements in tissues by XRF
Determination of elements in body fluids by XRF
Simultaneous multielement atomic absorption
spectrometry
Multielement studies using atomic absorption
spectrometry
Developments in single element techniques
Hair and nail analysis
Progress for individual elements
Aluminium
Arsenic
Bismuth
Boron
Cadmium
Calcium
Chromium
Cobalt
Copper
Gadolinium
Gold
Iron
Lead
Lithium
1.7.15
1.7.16
1.7.17
1.7.18
1.7.19
1.7.20
1.7.21
1.7.22
1.7.23
1.7.24
1.7.25
1.7.26
1.7.27
2
3
3.1
3.1.1
3.1.2
3.1.3
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.8.1
3.8.2
3.8.3
3.8.4
3.8.5
3.9
3.9.1
3.9.2
3.9.3
3.9.4
3.9.5
3.9.6
3.9.7
Magnesium
Manganese
Mercury
Molybdenum
Nickel
Phosphorus
Platinum and noble metals
Selenium
Silver
Strontium
Titanium
Uranides and actinides
Zinc
Analysis of drugs and pharmaceuticals, traditional
medicines and supplements
Analysis of foods and beverages
Sampling and sample preparation
Extraction
Digestion
Preconcentration
Speciation
Applications using hydride generation
Applications using flame atomic absorption
spectrometry
Applications using electrothermal atomic absorption
spectrometry
Applications using inductively coupled plasma-mass
spectrometry
Applications using other analytical techniques
Progress for individual elements
Arsenic
Lead
Mercury
Selenium
Other elements
Single and multi-element analysis of foods and
beverages
Dietary intake studies
Human milk and infant foods
Milk and dairy products
Wheat, flour and rice
Vegetables, nuts and fruits
Fish and seafood
Drinking waters and non-alcoholic beverages
This journal is & The Royal Society of Chemistry 2005
J. Anal. At. Spectrom., 2005, 20, 323–369
323
3.9.8
3.9.9
3.10
3.11
3.12
4
5
Alcoholic beverages
Other foods
Reference materials and collaborative trials
Packaging and cooking
Authentication of foods: provenance and origins
Conclusions
References
This annual review covers the literature on the analysis of
clinical and biological materials, foods and beverages using
atomic spectrometric techniques published in the year up to the
end of October 2004. Tables 1 and 2 summarise the details of
these publications. Our previous Update1 covered the preceding
year up to October 2003. This year, it is evident we are moving
into a new phase with many more papers appearing that used
dynamic reaction cells or octopole cells with quadrupole ICPmass spectrometers to reduce isobaric interferences, which are
so prevalent in biological applications. Innovation and
development were also noted with a ‘beam injection’ system for
FAAS and the extension of in vivo XRF determination to Ag
and As. Speciation of As and Se remains topical and the
increased complexity of the situation is now evident with
additional species found, many of which still have to be
identified. More than 30 years after the appearance of Itai-Itai
disease, a consequence of Cd contamination of rice in Japan, it
is evident that despite successful remediation work
concentrations of Cd in rice are still greater than elsewhere in
Asia. This, together with the continuing concern over As in
drinking water in Bangladesh, illustrates the importance of
vigilance in preventing such tragedies in the future. Abnormally
high As concentrations found in fossil skeletons of dinosaur
species have led to the suggestion that As toxicity could have
contributed to the extinction of dinosaurs in the Chinese
Province of Sichuan. Finally, it is appropriate to acknowledge
that this is the last Update for which David Halls will be
writing. It is not possible to do justice to all that he has
contributed. David has written for every one of the Clinical and
Biological Materials, Foods and Beverages ASUs since they
were established in 1986 and was the Topic Group Coordinator
for several years. His contributions are always carefully
crafted and, with his long practical experience within the
clinical environment, his insight and observations are given with
common sense and often with considerable humour too.
1 Analysis of clinical and biological materials
1.1 General reviews and articles
In a review entitled Biological fluids as a source of information
on the exposure of man to environmental chemical agents,
Polkowska et al.2 argued that because the concentrations in
biological fluids are low and the matrix complex, direct determination is not possible and some sample pretreatment is
necessary. They reviewed techniques for analyte isolation,
enrichment and determination for a range of organic and
inorganic pollutants and their metabolites.
1.2 Sampling and sample preparation
1.2.1 Sample digestion. A novel total combustion technique
was developed by Flores et al.3 Samples of biological material
were wrapped in paper and placed on a quartz holder in a
quartz vessel used in a commercial microwave oven. Ammonium nitrate was added to the paper and the vessel pressurised
to 15 bar with O2. Application of microwave radiation for 20 s
ignited the paper with rapid combustion. Residual C was 1.3%,
but when an additional reflux step with HNO3 was included, it
fell to o0.4%. Results for Cd and Cu in CRMs determined by
ETAAS were within 96–105% of certified values.
324
Trevizan et al.4 used acid vapour attack to partially digest
bovine liver in a modified microwave digestion system. Three
sample cups of 4 ml volume were supported in the glass
reaction vessel of the microwave oven. Samples of 50–90 mg
mass were weighed into the cups and a mixture of NaClO and
H2O2 was added. The cups were subjected to attack from the
vapour of HNO3–H2SO4 at 120 1C for 15–25 min. The
recoveries of Al, Ca, Cu, Fe, Mg, Mn and Zn were evaluated
after determination by ICP–AES. Most elements showed
quantitative recovery after 25 min heating of a 50 mg sample.
For difficult to extract elements, such as Al and Fe, recovery
improved when the sample particle size was smaller than
44 mm.
1.2.2 Solid sampling. As part of a study on the determination of Pd by solid sampling ETAAS, Resano et al.5 investigated the determination of Pd in the antihypertensive drug,
enalapril maleate. Low levels of Pd remain from the catalyst
used in synthesis. Drying and pyrolysis at 1200 1C of 7–10 mg
samples repeated five times allowed a total mass of 35–40 mg to
be introduced onto the platform. Direct calibration by aqueous
solutions was possible and this allowed determination down to
an LOD of 0.4 ng g1. The concentration found was 1.9 ng g1
and the method was thus suitable for monitoring concentrations which were expected to be below the legal limit of
20 mg g1.
The novel direct flame solid-sampling technique developed by
Flores et al. has been applied to the determination of Cu in
medicinal plants.6 In this technique, the sample, ground to a
particle size of less than 80 mm, is introduced as a dry aerosol
into a T-tube below the optical path in an air–C2H2 flame. The
aerosol passes through a slit in the tube into the optical path,
giving a transient signal which is integrated for 2 s. An LOD
for Cu of 0.8 ng was found which corresponded to 1.2 mg g1 if
a sample mass of 1 mg was used.
1.2.3 Sample preconcentration. Solid-phase extraction has
been explored to obtain greater sensitivity in FAAS. Ganjali
et al.7 used octadecyl-bonded silica disks modified with a Schiff
base (bis-2-thiophenalpropandiamine) to separate Cd, Cu and
Pb from environmental and biological samples. The metal ions
were subsequently stripped with acid. The LODs achieved were
0.01, 0.02 and 0.25 mg l1 for Cd, Cu and Pb, respectively.
Shamsipur et al.8 modified the octadecyl-bonded silica disks
with 1-hydroxy-2-(prop-20 -enyl)-4-(prop-20 -enyloxy)-9,10-anthraquinone to selectively separate Cu from the matrix to
obtain enrichment factors of 400 or greater. The LOD achieved
was 0.1 mg l1. The success of the method was demonstrated by
the determination of Cu in Bovine Liver SRM, tea leaves and a
synthetic sea-water sample. Cobalt and Ni were preconcentrated 200-fold by Gopikrishna et al.9 on solid benzophenone
as ethyl xanthate complexes at pH 8–10. The solid benzophenone together with metal complexes was subsequently dissolved in DMF for determination by FAAS. The method
was applied to the determination of Co and Ni in human hair
samples, with trueness demonstrated by analysing the CRMs,
NIES Human Hair No. 5 and IAEA Reference Hair HH1.
Cloud point formation with mixed micelles was developed by
Nascentes and Arruda10 for the preconcentration of Co. The
element was complexed with pyridylazo compounds in a mixed
surfactant medium of Triton X-100 and SDS. Phase separation
was induced by addition of either HCl or NaCl. Cobalt in the
surfactant-rich phase was then determined by FAAS. Under
optimised conditions, LODs of 1.1 and 1.6 mg l1 were
obtained with the use of HCl and NaCl, respectively. Results
obtained in the determination of Co in pharmaceutical compounds compared well with those obtained by ETAAS.
Further applications of online preconcentration in ETAAS
have appeared. Sung and Huang11 combined a laboratory-
made FI system with a multielement ETA-AA spectrometer to
enable the simultaneous determination of Bi, Cd and Pb in
urine. These elements were retained on a microcolumn of
Muromac A–1 resin positioned on the autosampler arm and
then eluted with 50 ml of 20% v/v HNO3 directly into the
graphite furnace. Calibration standards in 0.2% v/v HNO3
went through the same procedure. With a 213 ml sample loop,
10 samples h1 could be analysed and the LODs were 13, 2 and
4.5 ng l1 for Bi, Cd and Pb, respectively. Trueness was
demonstrated by analysis of the RMs, Seronorm Trace Elements Urine Level 1 and Level 2. Speciation of Cr in urine was
possible in a system developed by Siles Cordero et al.12 With a
microcolumn containing Amberlite IRA–910, CrVI was determined and, by replacing with a microcolumn containing silica
gel functionalised with 1-(di-2-pyridyl)methylenethiocarbonohydrazide, total Cr could be measured. The concentration of
CrIII was obtained by difference. The equipment used is
ingeneous as it uses many of the existing facilities on the
autosampler. The modified microcolumn replaced the autosampler tip and elution was carried out by sampling eluant
(40 ml of 2 M HNO3) and dispensing it into the graphite tube.
An external peristaltic pump and rotary valve, used for sampling, were controlled by an electronic control circuit which
was initiated by microswitches that were operated when the
sampler arm returned to its standby position. The sampling
process occurred while the furnace programme was running
with the previous sample. No CrVI was found in any of the
urine samples examined, although it was satisfactorily recovered from spiked urine samples. Anthemidis et al.13 endeavoured to obtain higher enrichment factors than are normally
possible with these on-line systems in ETAAS. They designed a
gravitational separator which allowed an organic extract to be
effectively separated from a large volume of aqueous phase. In
the determination of Cd in natural waters and urine samples by
ETAAS after extraction of the complex with ammonium
diethyldithiophosphate into IBMK, they obtained an enrichment factor of 24.6, giving an LOD of 2.8 ng l1.
and spinal nerves,17 it was found that accumulation of Ca and
P was only marked in the trigeminal nerve, with a significant
inverse correlation between the S concentration and the concentrations of the major elements, Ca, Mg and P. In human
tendons and ligaments,18 again only in one type, the posterior
longitudinal ligaments, an increase with ageing was found, this
time for Ca and Mg. Iron concentrations decreased significantly with ageing. In an attempt to see whether age-related
changes differed between races, these Japanese workers,19studied the accumulation of elements in the arteries and cardiac
valves of Thai subjects. They found that accumulation of Ca
was generally similar to that found in the Japanese, but was
higher in the coronary artery and lower in the thoracic aorta.
On-line preconcentration is often used to improve sensitivity
to allow other elements to be determined by ICP-AES. Yang
et al.20 used a microcolumn in an FI system to preconcentrate
and simultaneously determine Bi, Co, Cr, Cu, Y and Yb in
biological CRMs with good accuracy. The microcolumn contained nanometer-sized TiO2 loaded with 1-(2-pyridylazo)-2naphthol (PAN). To determine Hg in digested urine, hair and
blood samples, Anthemidis et al.21 complexed the Hg on-line
with APDC, retained this on PTFE turnings in a column of a
combined preconcentration–gas liquid separator module, released the Hg by reduction with SnCl2 and purged the Hg
vapor with Ar gas into the ICP. With a 60 s preconcentration
time, the LOD was 0.01 mg l1 and 30 samples h1 could
be analysed. At a concentration of 1.0 mg l1, the precision
was 3.1%.
1.3 Developments in and applications of multi-element techniques
1.3.2 Inductively coupled plasma mass spectrometry and other
mass spectrometric techniques
1.3.2.1 Reviews. Traditionally, TIMS has been used for
stable isotope studies in humans but, in a review, Sturup22
showed how advances in ICP-MS have led to a broader use
of this technique in nutritional research. Developments such as
single- and multi-detector ICP-MS and collision and reaction
cells have enabled isotope ratios to be measured more precisely
and interferences to be removed. The current and future use of
ICP-MS in this field was discussed.
1.3.1 Atomic emission spectrometry with the inductively
coupled plasma or microwave induced plasma. Matusiewicz
and Golik have demonstrated two alternatives to acid digestion in the determination of major and trace elements in solid
biological materials by MIP-AES. In the first,14 CRMs were
solubilised by TMAH with ultrasonic agitation. After dilution,
the suspensions were pumped to a V-groove Babington nebuliser feeding an Ar plasma. Concentrations of major (Ca, K,
Mg, Na) and trace (Cu, Fe, Sr, Zn) elements measured in
TORT–1 Lobster Hepatopancreas, IAEA–153 Milk Powder
and NIST 1577 Bovine Liver agreed satisfactorily with certified
values. In the second,15 samples were slurried in 10% v/v
HNO3 containing 0.01% v/v Triton X-100 and sprayed with
the V-groove nebuliser directly into the microwave cavity torch
assembly without desolvation. Calibration was by standard
additions. The precision ranged from 7% to 11% and accuracy
was demonstrated by the determination of Ca, Cd, Cu, K, Mg,
Mn, Na, P, Sr and Zn in three CRMs with satisfactory
agreement with certified values. In a further study, Matusiewicz and Kopras16 showed that the hydride-forming elements,
As, Bi, Ge, Sb and Se, together with Hg could be determined
simultaneously with good sensitivity by trapping the hydrides
and Hg vapour at 300 1C on a graphite tube pre-treated
with Pd and Au for electrothermal vaporisation at 2100 1C
into the MIP. However, the precision and accuracy of
the results reported on a range of CRMs leave something
to be desired and would suggest that further improvement
is necessary.
Age-related changes of major elements in parts of the human
body were studied using ICP-AES for determination. In cranial
1.3.2.2 Multielement determination by ICP-MS. Sector field
ICP mass spectrometers and quadrupole ICP mass spectrometers with collision or reaction cells have become more
common and are no longer a research curiosity. These instruments are now occasionally being described in applications
because that is what the laboratory has, rather than to solve a
problem that older ICP mass spectrometers could not solve.
Thus, this review no longer covers applications with these
techniques separately. Single element applications of ICP-MS
still predominate and these are covered in section 1.7. This
section deals with multielement applications.
If ICP-MS has a future in the multielement determination of
trace elements in serum and urine for a routine laboratory, the
method has to be simple. Nakagawa et al.23 examined the
determination of As, Cd, Cu, Fe, Pb, Se and Zn in urine after
simple dilution 10-fold with 1% v/v HNO3. Matrix interference
by NaCl was corrected by the use of added internal standards
In, Rh, Tl and Y. Because of isobaric interferences, Fe and Se
were measured in collision cell mode with H2–He as the cell
gas. A comparison was made with results obtained after
microwave digestion of the samples with generally good agreement; however, the acid decomposition introduced more matrix interference from the acid. Results on two urine CRMs
showed satisfactory agreement for As, Cu and Pb but results
for Cd and Se were higher than the certified or expected values;
there were no certified or recommended values for Fe in these
CRMs. Simple dilution was also used by de Boer et al.24 in
screening for 56 elements in blood and urine samples of a
population possibly affected by a firework explosion. Analysis
of CRMs and comparison of results with literature values
325
indicated that results were reasonable for Ba, Cd, Co, Cu, Ni,
Sb, Sr, Sn, Tl, Pb and Zn in urine and the same elements in
blood except for Ba, Ni, Sb and Sr. Giné et al.25 used on-line
dialysis and ID in their method for the determination of Cu,
Se, Pb and Zn in serum. The on-line dialysis removed 70% of
the Cl, K and Na, thus improving the accuracy by ensuring
freedom from matrix effects from the alkaline earths and
freedom from isobaric interferences in the determination of
63
Cu, 77Se and 66Zn. Since the recirculation of the sample
through the dialysis system took 10 min, one wonders how this
method, with its added complexity of ID, could possibly be
considered for routine analysis. Forte et al.26 measured Al, Ca,
Cu, Fe, Mg, Mn, Si and Zn in urine, serum, blood and
cerebrospinal fluid (CSF) of 26 patients with Parkinson’s
disease and 13 age-matched controls using ICP-MS and ICPAES. Calcium concentrations in blood, serum and urine and
Si in the urine were significantly elevated in the patients. This
might have been the result of adjuvants in pharmaceuticals that
they were taking. Iron concentrations were elevated in blood
and urine while serum Cu and Mg were significantly lower than
controls. The authors suggested that Cu and Fe were involved
in the pathogenesis of Parkinson’s disease.
Interferences in the determination of essential and toxic
elements in premature human milk were reduced by the use of
H2 in an octopole reaction cell in quadrupole ICP-MS. St.
Remy et al.27 demonstrated the reduction of isobaric interference for 52Cr, 54,55,56Fe and 77,78Se. Some interferences were
introduced by the cell, e.g., HBr1 affecting 80,82Se. Milk
samples were digested with HNO3–H2O2 in a microwave
system. Analysis of BCR skimmed milk powder CRM gave
results in agreement within the range for those elements (Ca,
Cu, Fe, Mg, Na, Pb and Zn) that had certified values. Results
on the human milk samples showed that the elemental composition changed during the lactating period. Formula milks used
for feeding premature babies showed important differences in
essential element composition from natural milk.
The elemental composition of plaque deposits in human
arteries and aorta was studied using ICP-MS. In calcified
plaque, Murungi et al.28 found that the molar ratio of Ca to
P suggested that a significant amount existed as hydroxyapatite, but the ratio varied from sample to sample, indicating
that other compounds were also present. In soft plaque, the Ca
and P concentrations were an order of magnitude lower but the
other elements (Al, Ba, Cu, K, Mg, Na, Pb, S, Si and Zn) were
present at concentrations of the same order of magnitude as
was found in calcified plaque. Comparison of the composition
of plaque deposits in human bypass coronary arteries and
native arteries by Thiam et al.29 showed no consistent difference. Calcium and P concentrations were relatively high in all
cases, but again the ratio did not correspond to hydroxyapatite. Stadler et al.30 were more concerned about the Cu and Fe
concentrations in plaque. Measurements of Cu and Fe in
healthy human arteries and in carotid lesions by ICP-MS
showed significantly elevated levels of Cu and Fe in the lesions.
Spectra obtained by EPR were characteristic of non-haem FeIII
complexes. They suggested that accumulation of Fe might
contribute to the progression of cardiovascular disease.
The performance of SF-ICP-MS for multielement analysis of
biological tissue samples was evaluated by Engstrom et al.31
Samples were digested with HNO3 using microwave heating.
Precision was better than 5% for the majority of the 68
elements and the results of analysis of CRMs were good for
all elements except Cl. For elements present in concentrations
above 2 mg g1, results were compared with those obtained by
ICP-AES; good agreement was obtained. Trace elements in
human brain tissue were determined by Gellein et al.32 using
SF-ICP-MS. Amyotrophic lateral sclerosis (ALS) and parkinsonism-dementia complex (PDC) were common neurodegenerative diseases in Guam in the 1950s and 1960s. Now,
fortunately, these diseases are on the decline. These researchers
326
measured the elements Cd, Co, Cu, Fe, Mn, Rb, V and Zn in
formalin-fixed brain tissue from eight Guamanian patients
with ALS, four with PDC and five controls. In ALS, Cd
concentrations were significantly elevated in both grey and
white matter. In PDC, Zn was significantly elevated in grey
matter. Other differences were found to be insignificant.
As part of a study on the effect of chronic exposure to Cd on
the intracellular accumulation of essential elements in cultured
human intestinal cells (Caco-2 TC7), Noel et al.33 developed a
rapid method using closed vessel microwave-assisted digestion
and ICP-MS. Three elements, Be, In and Sc, were used as
internal standards in the measurement of Ca, Cd, Cr, Cu, Mg,
Mn, Mo, Na and Zn. Trueness was demonstrated by the
analysis of CRMs and by comparison of results obtained for
cells and CRMs with those obtained using ETAAS or FAAS.
The results were in good agreement.
The release of metals from metallic implants was studied by
Okazaki et al.34 in a rat model. The tibia tissues near the
implant were lyophilised, acid digested with microwave heating
and the metals determined by ICP-MS. Iron was separately
determined by ETAAS. Of the four types of alloys examined,
the lowest release was from a Ti-15Zr-4Nb-4Ta alloy.
1.3.2.3 Laser ablation ICP-MS. The potential of LA-ICPMS for determination of trace elements in a gel after gel
electrophoresis was explored by Chery et al.35 For the elements
Ag, As, Cd, Cr, Cu, Li, Mn, Mo, Ni, Pb, Pd, Pt, Se, Tl, V and
Zn, they measured LODs, repeatability and linearity. The
technique was applied to the determination of selenoproteins
in extracts of red blood cells after a one-dimensional (1D)
separation and to a two-dimensional (2D) separation of selenoproteins in yeast. Better results were obtained by the use of a
DRC to remove isobaric interferences. Of the gases tried in the
cell, CO was found to give the best results. Becker et al.36
separated human brain proteins by 2D gel electrophoresis and
determined Al, Cu, S, Si and Zn in the protein spots by an LA
system coupled to a SF-ICP-mass spectrometer. Ion intensities
for P, Si and the metals were expressed as a ratio to the S ion
intensity.
Laser ablation coupled to a TOF-ICP-mass spectrometer
enabled Kindness et al.37 to produce 2D maps of Cu and Zn in
liver sections. Use of C as an internal standard improved
reproducibility. On a section of sheep liver the precision was
9–47% for Cu and 4–21% for Zn using a line scan. For a raster
scan, precisions were 27–59% for Cu and 8–18% for Zn.
Although the concentrations of Cu found in the sheep liver
were extremely low, the distribution could be mapped.
Laser ablation ICP-MS was applied by Uryu et al.38 to the
determination of Pb in the tooth enamel of deciduous incisors.
Pelletised bone CRMs were used as calibrants to measure the
Pb : Ca ratio. The low LOD (11 mg kg1) was adequate to
measure Pb concentrations found in the tooth enamel of
unexposed individuals (0.1–10 mg kg1). Results obtained for
Pb : Ca ratios correlated well with those obtained after
digestion of tooth enamel and analysis of the digests.
1.3.2.4 Secondary ion mass spectrometry. The high sensitivity
of SIMS enabled Galle et al.39 to study the removal, by the
lysosomes of the proximal renal tubular cells, of elements at a
much lower concentration than was possible with EPMA.
Studies with EPMA required such high doses that the precipitation processes seen were possibly a consequence of the
high concentrations used. They studied the elimination of Al
and In from the rat kidney and found that these elements, even
at ppm concentrations, were removed from the extracellular
fluid by the lysosomes within a few hours. The distribution of
Gd in human glioblastoma cells treated with a Gd-containing
magnetic resonance imaging (MRI) agent was studied by
Smith et al.40 Neutron capture therapy with 157Gd for brain
tumours such as glioblastoma multiforme was being developed
and the authors wished to have a technique suitable for
studying the subcellular distribution of Gd. Microscopy with
SIMS showed 157Gd mainly concentrated in the cytoplasm of
the cell, but distributed very heterogeneously. The other six
naturally abundant isotopes of Gd showed a similar distribution. The more usual isotope for neutron capture therapy is
10
B. Oyedepo et al.41 used a laboratory-made SIMS system to
image cultured tumour cells incubated in media containing
known 10B concentrations and intracranial tumour tissue from
animals previously injected with [10B]-p-boronophenylalanine.
Calibration for B in tissue standards was made by correlating
the measured 10B : 12C ratio with the total B concentration
measured by ICP-AES. Ion maps of 10B, 12C, 39K and 23Na
and were produced.
1.3.2.5 Accelerator mass spectrometry. Using 26Al as a tracer
and detection by AMS, Steinhausen et al.42 measured the
absorption, distribution, speciation and excretion of Al in six
healthy human volunteers. Typical absorption of Al from
AlCl3 was 0.1% and, in serum, the ultrafiltrable fraction of
Al was found to be 5.6%. Yumoto et al.43 found, in rat studies,
that 26Al was transferred into suckling rats from maternal milk
and persisted in the cerebrum, cerebellum and spinal cord long
after the young rats were weaned. However, although the liver
and kidney Al concentrations, as measured by AMS, increased
significantly through transfer from the maternal milk, after
weaning the concentrations decreased remarkably. They concluded that considerable amounts of Al taken up into the
brains of the suckling rats from maternal milk remained in
their brains throughout their lifetime.
1.3.3 X-ray fluorescence spectrometry
1.3.3.1 Reviews. The application of XRF in medical sciences
has been reviewed by Borjesson et al.44 Recent advances in
in vivo methods and their applications were detailed.
1.3.3.2 Elemental mapping. Mapping of elements in brain
tissue has been carried out by microbeam SRXRF. The
distribution and chemical state of Fe in substantia nigra in
Parkinson’s disease were examined by SRXRF and Fe K-edge
X-ray near-edge structure spectroscopy, respectively, in a study
on monkey brain tissue by Ide-Ektessabi et al.45 The SRXRF
mapping was carried out with a 7.16 keV beam, while the
chemical state analysis was performed between 7.16 and 7.12
keV energies. The Fe21 : Fe31 ratios in the neuromelanin
granule showed significant variation but correlated with the
total Fe concentration. In cells having high Fe concentration
most was present as Fe21. As Fe21 has been shown to promote
free radical formation, this could have been a factor leading to
cell death. The distribution of elements in Parkinson’s disease
and amyotrophic lateral sclerosis was studied by SczerbowskaBoruchowska et al.46 A 5 by 2 mm beam scanned human brain
and spinal cord tissue sections to produce 2D maps which were
compared with histopathological examination. The spatial
distribution of certain elements corresponded to the pattern
seen under the microscope. Accumulation of elements in the
nerve cell bodies and white matter was noted when the patient
samples were compared with controls. Liu et al.47 compared
the distribution of elements in the brains of iodine-deficient
and iodine-supplemented rats. The iodine-deficient rats had
higher Br, Ca, Cl and Zn and lower Cu and Fe concentrations
in the cerebral cortex.
The changes that occur around metallic prostheses coated
with biological glasses were followed by Barbotteau et al.48
using microbeam PIXE. One type of glass disappeared after
3 months of implantation to be replaced by bony tissue. They
showed that Ti release from the Al–Ti–V alloy began when the
metal was exposed to biological fluids, but after a few months
of implantation the Ti contamination was stabilised and
remained within 30 mm of the surrounding bone.
1.3.3.3 Developments in in vivo XRF determination. The
feasability of using in vivo determination of Ag in skin was
examined by Graham and O’Meara.49 A 125I source was used
with the detector at 901 to the source. Using silver-doped skin
phantoms, 3–4 ppm of Ag could be detected in a 10–20 min
detection period, which suggested that it could be used for
monitoring patients for argyria, an irreversible skin pigmentation resulting from exposure to Ag. Similarly, Studinski et al.50
examined the determination of As in skin using a 109Cd source.
The LODs were 3.5 and 10.3 ppm for 901 and 1801 geometries,
respectively, for a measurement time of 30 min.
A phantom-based feasability study was carried out by
Shilstein et al.51 for the in vivo determination of Zn in prostate.
Their method would allow determination through a 2–3 mm
thick layer of the rectal wall using an XRF topographic
technique with minimal interference from Zn in non-prostatic
tissue. A special transrectal probe for this was under development. The reason for this interest is apparent from an earlier
study from the same group52 in which in vitro XRF measurements were made of Zn in prostate samples taken at surgery.
There was a close relationship between prostatic Zn and
prostate specific antigen in blood. They believed that a combination of the two measurements would improve the separation
between prostate cancer and benign prostate hyperplasia and
thus allow more accurate diagnosis. The Zn concentration in
prostate was not uniform so that they concluded that several
measurements would need to be made at various locations.
1.3.3.4 Determination of elements in tissues by XRF. In a
further publication on differences between Greenlandic Inuit
and Danes, Milman et al.53 reported concentrations of Se in
liver measured by XRF. The higher Se content in the Inuit
(mean 26.6 mmol kg1 dry mass) than in Danes (17.7 mmol
kg1) was due to a higher Se intake from fish and meat from
sea mammals. Inuit men showed a negative correlation between liver Se concentration and age, whereas Danish men
showed a positive correlation. There was no similar correlation
for the women of both races. Concentrations of Cu, Fe and Zn
in biopsy samples of the liver of patients with chronic hepatitis
or hepatic cirrhosis caused by the hepatitis C virus were
measured by Ebara et al.54 using PIXE. Comparison with
controls showed that the only factor significantly different
was the higher Cu content in the liver parenchyma.
Differences in the concentrations of selected elements in
primary and permanent teeth were reported by Gierat-Kucharzewska et al.55 Total reflection XRF was used to analyse the
roots and crowns from the caries-affected teeth of 27 children
aged from 4 to 11 y and 36 adults between the ages of 36 and
71 y. Concentrations of Cu, Mn, Pb and Sr were higher in
permanent teeth than in primary teeth, while concentrations of
Ca, Cr and Fe were similar. Concentrations of Ni and Zn were
higher in the teeth of children than those of adults.
1.3.3.5 Determination of elements in body fluids by XRF.
Total reflection XRF using the Compton peak as internal
standard enabled Hernandez-Caraballo and Marco-Parra56
to measure Cu, Fe, Se and Zn in serum samples from 27 cancer
patients and 33 controls. Artificial neural networks were
evaluated to use the data for prediction of disease. In the
cerebrospinal fluid of patients with amyotrophic lateral sclerosis, Ostachowicz et al.57 found that Cl and Zn concentrations
differed significantly from those of controls. They measured Br,
Ca, Cl, Cr, Cu, Fe, K, Mn, Ni, Rb and Zn by TXRF.
Concentrations of Br, Ca, Cu, K, Pb, Rb, S and Zn in whole
blood samples of a non-occupationally exposed population
living in Mexico Valley were measured by Martinez et al.58
using TXRF. Comparison of the results with those reported
for other countries showed that Ca, Cu, Pb, Rb, S and Zn
concentrations were similar while Br and K were higher,
possibly related to differences in diet, geography and environJ. Anal. At. Spectrom., 2005, 20, 323–369
327
mental factors. The Pb results were also covered in a separate
publication.59 To improve the LOD for Pb, Fe was removed
from the digested sample by extraction. The results obtained in
2001 (geometric mean: 2.00 mg dl1) were much lower than
those obtained in 1980 (geometric mean: 22.2 mg dl1), reflecting a general decrease in environmental Pb exposure.
Changes in Cu, Fe and Zn concentrations in the erythrocytes
and serum of patients with thyroid disorders before and after
131
I therapy were studied by Zhang et al.60 using XRF. The
changes seen were related to the change in the thyroid status
after therapy. Both serum Cu and Zn showed a significantly
positive correlation with triiodothyronine (T3) and thyroxine
(T4). However, no differences were found in the erythrocyte Cu
and Zn, except that erythrocyte Zn concentration showed an
increase in patients with hypothyroidism and a marked negative correlation with T3 concentration.
1.3.4 Simultaneous multielement atomic absorption spectrometry. For this technique, there is a need to choose elements of
relatively similar volatility, as compromise conditions will be
needed for pyrolysis and atomisation. Hsiang et al.61 determined the four elements As, Co, Mn and Ni using Pd as a
modifier. For the THGA, optimal compromise furnace temperatures were 1350 1C for pyrolysis and 2100 1C for atomisation. Improved recovery for As was obtained when the
pyrolysis stage was split into two, the first with 5% H2–95%
Ar as the internal gas and the second with pure Ar. Recoveries
in urine for the four elements ranged from 88% to 95%.
Trueness was confirmed by determination of the elements in
the RM Seronorm Trace Elements in Urine. A W–Rh permanent chemical modifer was used by Correia and Oliveira62 in
the determination of Cd and Pb in whole blood. Temperatures
of 400 1C and 1500 1C for pyrolysis and atomisation were
chosen. Samples were diluted 1 þ 9 with a diluent containing
0.11% m/v Triton X-100 and 1.1% v/v HNO3. Calibration by
simple aqueous standard solutions was shown to be accurate
and verified by analysis of three Seronorm RMs. For determination of Cd and Pb in urine,63 they used an end-capped
graphite atomiser to obtain greater sensitivity (14% for Cd
and 25% for Pb). Samples were diluted 1 þ 4 with a diluent
containing Triton X-100, HNO3 and NH4H2PO4, the latter
acting as the chemical modifier. Pyrolysis was at 500 1C and
atomisation at 1800 1C. Again, calibration with simple aqueous standards was shown to be accurate. In both methods for
blood and urine, furnace programme times were minimised—
63 s for blood and 57 s for urine.
1.4 Multielement studies using atomic absorption spectrometry
The effect of whole body irradiation on tissue Cu, Fe, Mg, Mn
and Zn concentrations was studied in a rat model by Cengiz
et al.64 The results obtained on analysis of heart, lung and kidney
samples by FAAS showed that Cu and Fe had significantly
increased in the kidney, but there were no significant changes in
the concentrations of all the elements in the heart and lung.
Trace elements in pregnancy remains a popular theme for
study. Awadallah et al.65 followed changes in plasma concentrations of Cu, Fe and Zn in 186 Jordanian women using
measurements by FAAS. Iron concentrations remained similar
in the three trimesters but plasma Cu increased and Zn
decreased. In the third trimester, anaemic women (haemoglobin o11.0 g dl1) had significantly lower plasma Fe and Zn
concentrations than non-anaemic women. The concentrations
of Cu and Fe were significantly higher in cord blood than
maternal blood, whereas the Zn concentration was lower.
There was a significant positive correlation between the neonatal birth weight and the cord blood plasma Zn concentration. A further indication of concern about depletion of Zn
came in a study by Cengiz et al.,66 who recommended Zn
328
supplementation along with folic acid in pregnancy. They
studied women whose pregnancies were terminated because
of foetal neural tube defects and found significantly lower
serum Se and Zn concentrations than in women with normal
pregnancies. Whole blood Pb and plasma Cu were higher than
the controls. Copper and Zn were measured by FAAS, Pb by
ETAAS and Se by HGAAS. Effects of Ca, Mg, Pb and Zn on
the development of hypertension in pregnancy were studied by
Magri et al.67 Comparison of results on 33 women in the third
trimester of pregnancy with results from 110 normotensive
pregnant women showed no difference in plasma Ca (ionised
and total), Mg and Zn. Blood Pb, however, was significantly
related to blood pressure, even after correcting for age and
body mass index. Reduction of environmental exposure to Pb
was seen as an important priority.
Studies are increasing our knowledge of trace elements in
cancer. Kizilay et al.68 measured concentrations of Cu, Fe, Se
and Zn by AAS in acid digests of diseased larynx and skin
tissues from patients with epidermoid cancer. Comparison with
results from healthy tissues from patients without cancer
showed that the diseased tissues had significantly lower Fe
and Se concentrations. Copper and Zn concentrations were not
markedly different. Interpretation of changes in plasma trace
element concentrations in cancer are complicated because of
the effect of the inflammatory response. Mayland et al.69 used
C-reactive protein (CRP) as a marker of the inflammatory
response and measured by AAS techniques, Cu, Mn, Se and Zn
in the blood of 50 patients with various malignancies.
Although concentrations of Se and Zn were often lower than
the respective reference ranges and Cu and Mn higher than the
reference range, none of these elements showed a significant
correlation with CRP. The results suggest that the inflammatory response does not fully explain the reduction of Se and Zn
in cancer and depletion of these elements should be considered.
Infection with HIV is associated with changes in trace
element concentrations. In 45 Nigerian patients diagnosed as
HIV-positive, Ajayi and Omilabu70 found that the plasma Mg,
Se and Zn concentrations were significantly lower than those in
healthy controls and all three measurements correlated with
the CD4 lymphocyte count. Copper did not show the same
relationships. The authors suggested that supplementation of
these patients with Mg, Se and Zn would be helpful.
Analysis of pus is uncommon, but as Bryant et al.71 pointed
out, knowledge of the composition of pus can help understand
how the host defends itself against microbial growth. They
used AAS to measure Ca, Cu, Fe, Mg and Zn and fluorimetry
to measure Se in pus. Iron and Zn concentrations exceeded
those in normal serum. Calcium concentrations were 2- to 3fold lower than in serum while Mg was 2- to 3-fold higher.
In a study on patients with childhood asthma, Kocyigit
et al.72 found increased plasma Fe and decreased plasma Se,
which they thought might be responsible for the oxidant/
antioxidant imbalance in these patients. Compared with
healthy controls, the patients had significantly lower plasma
Mn, Se and total antioxidant capacity (TAC) and significantly
higher plasma Fe and malondialdehyde concentrations. Plasma Cu, Zn and albumin concentrations did not differ significantly.
Massanyi et al.73 reported concentrations of Cd, Cu, Fe, Ni,
Pb and Zn in the semen of the bull, ram, boar, stallion and fox.
In fact they reported it before in a publication in 2003 which
was covered in last year’s Update.1 For those who are interested in repeats, rams have the highest concentrations of Cu,
Fe and Pb, boars the highest Zn and bulls the highest Ni. The
concentrations of Cd are similar in all species.
Kosmala et al.74 believed that they might have discovered
evidence that low level Cd exposure might contribute to the
development of left ventricular diastolic dysfunction in patients
with coronary artery disease. Using AAS techniques, they
measured blood Cd and Pb, serum Cu, Se and Zn in samples
from patients with indices of left ventricular diastolic dysfunction and in samples from subjects with normal coronary
arteries. None of the subjects were occupationally exposed to
heavy metals. The results did not show a significant difference
between the two groups, but, on univariate and multivariate
analysis, blood Cd significantly correlated with echocardiographic parameters of left ventricular diastolic function, mitral
inflow velocity ratio and deceleration time of inflow. Other
metals did not show this correlation and the correlation was
absent in the control group.
1.5 Developments in single element techniques
Surprisingly, there appear to have been no significant developments in novel AAS or AFS techniques as applied to clinical
and biological analysis and there is nothing to report.
1.6 Hair and nail analysis
Hair and nail arsenic measurements have been used in studies of
high As exposure in West Bengal. Mandal et al.75 found that
hair, fingernail and urine As concentrations correlated positively with water As concentration and recommended nail As
as a biomarker of exposure in affected areas. Speciation of
water extracts of hair and fingernails showed mainly AsIII (hair
58.9%; nail 62.4%) and AsV (hair 34.8%; nail 20.2%) with
smaller amounts of MMA and DMA. Whether this reflects the
speciation of As in the hair and nails is a relevant question, as
the inorganic and organic As species may show different
binding affinity to the proteins in hair/nails. According to
Samanta et al.,76 As is not the only toxic element involved in
this problem in West Bengal. Using ICP-MS, they measured
ten elements in digests of hair, nails and skin scales taken from
subjects in the affected area. The results showed not only high
As concentrations, but also Mn, Ni and Pb concentrations
higher than expected from other literature data.
The use of hair and nail Cd and Pb concentrations for
assessing exposure was evaluated by Mehra and Juneja.77 In
occupationally exposed subjects, hair Cd and Pb concentrations ranged from 0.01 to 22.1 mg g1 and 1.02 to 409.7 mg g1
and nail Cd and Pb from 0.21 to 35.7 mg g1 and 8.13 to 765.3
mg g1, respectively. For both elements, there was a significant
correlation between hair and nail levels. In a population
minimally exposed to these elements, hair Cd and Pb concentrations ranged from 0.11 to 1.16 mg g1 and 0.12 to 25.16 mg
g1 and nail Cd and Pb from 0.03 to 8.11 mg g1 and 1.08 to
65.6 mg g1, respectively. In this group a correlation between
hair and nail levels was found for Cd, but not Pb. There were
significant differences between the exposed and unexposed
group for hair Pb, nail Pb, nail Cd but not hair Cd. It would
have been interesting if this study had included a comparison
with blood Cd and Pb concentrations. Gan et al.78 improved
the sensitivity 13.4-fold in the determination of Pb in human
hair by FAAS through the use of HG with K3Fe(CN)6–HCl.
The LOD was 2.8 mg l1 and recovery of added Pb was in the
range 96–99%.
In a study of the temporal variation of blood and hair
mercury concentrations in pregnancy in a population living
along the St. Lawrence River in Canada, Morrissette et al.79
found that Hg exposure was related to fish consumption.
However, fish on the general market as fresh, frozen or canned
fish was a more important source than local fish. Blood and
hair Hg concentrations, measured by CVAAS and CVAFS,
respectively, correlated well with each other. Both blood and
hair concentrations fell in the second and third trimester of
pregnancy. The cord blood Hg concentration was significantly
higher than the maternal blood Hg concentration at birth.
There is not very convincing evidence that the concentrations of essential elements in hair and nails are a satisfactory
measure of nutritional status, except perhaps for Se. Never-
theless, many studies begin with the assumption that hair or
nail measurement is a useful guide. Rush et al.80 examined
whether there was seasonal variation in hair Zn concentration
in an apparently well-nourished New Zealand population.
Samples were washed, digested with HNO3 and Zn determined
in the digest by FAAS. No seasonal variation was found and
hair Zn was unrelated to hair colour, dietary variety, ethnicity
and gender in this population. Changes in hair and plasma Zn
during pregnancy were studied by Cavdar et al.81 using FAAS
for the determination. Both plasma and hair Zn concentrations
decreased significantly in the second trimester of pregnancy.
Although there was a significant difference between plasma Zn
in a well-nourished group and a poorly-nourished group, hair
Zn concentrations were not significantly different. A study
from southern Sweden82 compared the concentrations of 34
elements in the hair of 47 females living in an area with
drinking water of low pH with those found in the hair of 43
females living in an area with alkaline drinking water. Measurements in hair digests and in drinking water were by ICPAES and ICP-MS. Concentrations of Ca, Fe, Mo, Se and Sr
were higher in the alkaline group, while B and Ba were
significantly higher in the acid group. There was a positive
correlation between the hair and water concentrations for Ca,
Mo, Pb and Sr. The authors concluded that this indicated the
importance of intake from drinking water, but can they be
right? This is the same type of water that the subjects regularly
use to wash their hair and could this not just be exogenouslybound element? Lipsky et al.83 compared toenail Se concentrations in patients with prostate cancer with controls and found
no significant difference. Measurements were by DRC-ICP-MS
after microwave-assisted digestion of the samples. No correlation was found between nail Se and age, body mass index and
smoking status. The authors questioned the protective effect of
Se on prostate cancer, but perhaps they should have also
questioned how reliable toenail Se concentrations were as an
indicator of Se status.
1.7 Progress for individual elements
1.7.1 Aluminium. Two groups described studies on Al metabolism using 26Al tracers. Steinhausen et al.42 monitored Al
absorption, distribution and excretion in six healthy volunteers
and two patients with chronic renal failure, following a single
administration of 26Al. Serial blood and urine samples were
collected and the concentration of 26Al determined using AMS.
In the same work, the time dependence of 26Al binding to low
Mr serum species was also investigated. The authors reported
absorption rates of the order of 103 for AlCl3 and observed
differences in the rates of Al absorption and excretion between
healthy volunteers and individuals with chronic renal failure.
Yumoto et al.84 determined the uptake of Al from maternal
milk into the brain of suckling rats using a 26Al tracer. Tissue
concentrations of Al were quantitatively determined using
AMS. Lactating rats were injected subcutaneously with
26
AlCl3 from day 1 to day 20 post-partum and suckling rats
weaned at day 21 post-partum. Concentrations of Al in
cerebrum, cerebellum, spinal cord, kidney and liver increased
significantly in suckling rats between day 5 and day 20. Whilst
Al concentrations in liver and kidney declined rapidly after
weaning, up to 20% of the Al present in brain tissue at day 20
remained in the tissue at day 730 post-partum. The researchers
concluded that a significant proportion of Al taken up in the
brain of suckling rats remains in the brain throughout their
lifetime.
The renal handling of Al was investigated in two studies that
applied particularly innovative approaches. Shirley and colleagues85 combined micropuncture sampling with ETAAS to
determine Al concentrations along the renal nephron. Anaesthetised rats were infused with different doses of AlCl3 and
micropuncture samples taken from the Bowman’s capsule,
329
proximal convoluted tubule and early distal tubule for quantitative determination of Al. The authors reported that filtration
into the Bowman’s capsule was significantly greater than that
predicted by an in vitro model and was essentially freely
filtered. They concluded that Al, when complexed with citrate,
was efficiently excreted through a combination of glomerular
filtration and minimal re-absorption. Galle et al.39 used SIMS
to examine the subcellular localisation of Al and In in lysosomes of rat kidney proximal tubule cells. Within a few hours
of administration of low physiological doses of the two elements, lysosomes had extracted the elements from the extracellular fluid and precipitated them as insoluble phosphate
salts. They hypothesised that this concentration and precipitation mechanism was a physiological process rather than purely
pathological process for renal handling of Al and In.
Polec-Pawlak et al.86 combined both HPLC and CE with
ICP-MS to investigate intracellular binding of AlIII in neuroblastoma cells incubated with aluminium lactate. They reported that exposed cells synthesised a low Mr ligand, which
bound all metabolised AlIII as a negatively charged complex.
The ligand could not be characterised, however, either by
ES-MS or by its chromatographic behaviour.
1.7.2 Arsenic. This review period has continued to see
further work on the characterisation and quantitative determination of As species and metabolites in biological matrices.
B’Hymer and Caruso87 presented a comprehensive review on
the application of HPLC coupled with ICP-MS for arsenic
speciation in biological and environmental samples. Several
groups have determined As species in human urine. The study
by Sloth et al.283 determined As species in two human urine
CRMs (NIES 18 and NIST2670a) and urine quality control
materials. Samples were diluted 1 þ 3 v/v and As species
separated by gradient chromatography on cation and anion
exchange columns for quantitative determination using
ICP-MS. Nine As species were determined in the urine samples. Two of these dimethylarsinoylacetic acid and trimethylarsoniopropionate were reported for the first time in human
urine. The calculated sums of the individual species matched
the reference value for total As in the reference materials. In an
important study, Hansen and colleagues89 cautioned on the
need for correct characterisation of As metabolites in urine.
The authors described the generation of a sulfur containing As
species when DMAV was reduced by Na2S2O5–Na2S2O3. This
species could, they argued, be mistaken for the highly toxic
DMAIII species. They characterised the species as dimethylarsinothioic acid by HPLC-ICP-MS coupled simultaneously to
HPLC-ES-MS and ES-Q-TOF-MS and identified the species
as a naturally occurring As metabolite in the urine and wool of
sheep consuming high quantities of arsenosugars in a seaweed
diet. In a similar vein, Lai and colleagues90 reported markedly
different patterns of urinary As excretion in subjects consuming seafood. The researchers noted arsenobetaine (AB) and
DMA were the major urinary As species together with a
significant amount of an unknown species. They noted that
two volunteers eliminated high quantities of AB even though
no arsenic rich seafood had been consumed 72 h before urine
sampling. They argued that a better understanding of human
As metabolism is still needed. Shinohara et al.91 separated five
As species, AsV, MMA, DMA, AsIII and AB from human
urine using HPLC with an eluent containing 10 mM NH4NO3,
0.05% HNO3 and 0.1 mM EDTA. Three further As species,
arsenocholine, TMAO and TMI were subsequently co-eluted
in a single peak. The concentrations of the As species were
quantitatively determined by coupling the eluent from the
chromatograph directly to the nebuliser of a hexapole collision
cell ICP-mass spectrometer. As with Lai and colleagues, different patterns of excretion of As species were noted by these
authors which were due to different dietary habits of the
330
volunteers. Okina et al.92 described a method for the determination of trivalent methylated As species in rat urine using LCICP-MS. Rats were administered either DMAV or MMAV at
200 mg ml1 in drinking water. The trivalent species were
extracted from the urine matrix by complexation with DDC
into CCl4 and the trivalent species DMAIII and MMAIII
quantitatively determined. It is pertinent to note the likely
problem of using this method in many countries where restrictions have been placed on the use of CCl4.
Sample digestion methods for the quantitative determination of As in blood and urine were investigated by Syaslova
and Sperackova.93 For urine samples, dry ashing with
Mg(NO3)2 and microwave digestion with (NH4)2S2O8 were
both satisfactory for the quantitative determination of As
using ETAAS. For blood samples, complete recovery of spiked
As was achieved with a two-stage digestion process involving
microwave digestion with HNO3–H2O2 followed by dry ashing
on a hot plate. Bruhn et al.94 evaluated In, Pd and Rh as
permanent chemical modifiers for the determination of As in
digests of human hair and marine biological matrices using
ETAAS with a tungsten coil atomiser. A 1.9-fold improvement
in relative sensitivity was reported for 2 mg of Rh pre-reduced
on the tungsten filament and this treatment extended the
lifetime of the atomiser to 300–400 firings. An absolute LOD
of 29 pg was reported and the method validated by analysing a
number of CRMs. The authors used the method to monitor As
concentrations in the hair of exposed workers. A very sensitive
and precise method for the determination of As in microtomed
cross-sections of human hair using nano-SIMS was described
by Audinot and colleagues.95 The authors suggested that the
method may be sufficiently sensitive to differentiate As in the
medulla, cortex and cuticle and so distinguish As intoxication
by ingestion from surface contamination.
Whilst studies on As are normally related to the toxicity of
the element, two groups reported studies on the therapeutic
potential of As2O3 for treatment of solid tumours. Shen et al.96
treated esophageal carcinoma cells transplanted into immunodeficient mice with intra-tumour injections of As2O3. Concentrations of As in the tumour and other organs were determined
using AAS. Levels of As remained high in the tumour tissue
and were accompanied by apoptosis and necrosis of tumour
cells. Arsenic was also detected in other organs but no pathological changes were observed. Kito et al.97 examined the effect
of i.v. or intra-tumour administration of As2O3 on an hepatocellular carcinoma murine xenograft. Tissue concentrations of
As were determined using PIXE and the authors noted that As
accumulated more in the tumour than other tissues. Both
groups hypothesised that intra-tumour administration of
As2O3 has potential for the treatment of solid tumours.
Finally, in a departure from other mass extinction hypotheses, a role for As in the mass extinction of dinosaurs was
suggested by Zhou et al.98 The authors determined As in fossil
skeletons of four dinosaur species using HG-AFS. Samples
were digested with aqua regia in a boiling water bath and an
LOD of 0.03 mg l1 was reported. The As concentrations
determined were abnormally high and together with other
available data supported the hypothesis for As toxicosis as a
contributory factor to the mass extinction of dinosaurs in the
Sichuan Province of China.
1.7.3 Bismuth. Sung and Huang11 used a laboratory-made
FI system coupled to simultaneous ETAAS for the simultaneous determination of Bi, Cd and Pb in urine. Metal ions were
adsorbed onto a Muromac A-1 resin micro-column and eluted
directly into the graphite furnace using 20% v/v HNO3. Aqueous standard solutions taken through the same pre-concentration step were used for calibration. Reported LODs for a
213 ml sample loop were 13 ng l1, 2 ng l1 and 4.5 ng l1 for
Bi, Cd and Pb, respectively. The method was validated by
analysing a urine RM at two concentration levels. Determined
values for the three elements were between 90% and 110% of
the reference values.
1.7.4 Boron. A sensitive method for the determination of B in
small volumes of undigested plasma and urine using ID-ICP-MS
with DIN sample introduction was described by Bellato et al.99
One ml samples were spiked with enriched 10B solution and
equilibrated for 1 h. Proteins were precipitated with HNO3 to
remove interferences from C on the 11B signal. Aliquots (50 ml)
of the supernatant were directly introduced into the plasma for
measurement of 10B : 11B isotope ratios. An LOD of 0.6 mg l1
was reported. Total B concentrations in plasma ranged between 100 and 135 mg l1 and between 0.5 and 3.02 mg l1 in
urine. Oyedepo et al.41 described the results of preliminary
studies on the use of SIMS to determine 10B in cultured tumour
cells incubated with p-boronophenylalanine (BPA) and in
tumorous brain tissue of animals injected with BPA. Calibration was performed by analysing tissue standards and correlating the B : C ratio determined by SIMS with the total B
concentration determined by ICP-AES. The researchers identified 10B hotspots in brain tissues and the intracellular localisation of 10B in cultured cells. They concluded that SIMS could
show the distribution of 10B at ppm levels in cells and normal
and cancerous brain tissues.
Muhtaroglu100 examined the relationship between serum
and urine B and bone markers in menopausal women. Serum
and urine B were determined using ETAAS with a pyrolytically
coated tube. Both serum and urine B levels were significantly
lower in menopausal women compared with a control group.
The authors hypothesised that the low levels were due to low
intake of B by menopausal women.
1.7.5 Cadmium. Hernandez-Caraballo et al.101 described an
extremely fast method for the direct determination of Cd in
urine using ETAAS. Urine samples were diluted 1 þ 1 v/v with
4% HNO3 and 10 ml volumes injected into a transversely
heated graphite atomiser pre-heated to 110 1C. The normal
drying and pyrolysis steps were substituted with a 300 1C
drying step and the lack of a chemical modifier other than
HNO3 allowed an atomisation temperature of 1200 1C. The
total thermal cycle was reduced to 42 s. An LOD of 0.12 mg l1
was reported for the optimised conditions and the method was
validated by analysis of a human urine RM. A rapid method
for the simultaneous determination of Cd and Pb in whole
blood using ETAAS was described by Corriea et al.62 A
mixture of Rh and W was used as a permanent chemical
modifier, allowing compromise pyrolysis and atomisation temperatures of 400 1C and 1500 1C, respectively, and a total
furnace programme time of 63 s. Blood samples were diluted
1 þ 9 v/v with 0.11% Triton X-100 and 1.1% HNO3 and
calibration was performed with aqueous standards. The method was validated by analysis of whole blood CRMs and the
reported LODs were 0.03 mg l1 and 0.8 mg l1 for Cd and Pb,
respectively. The same workers63 also described a method for
the simultaneous determination of Cd and Pb in urine using
ETAAS. For this matrix, the researchers used an end-capped
transversely heated atomiser and an NH4H2PO4 chemical
modifier. Urine samples were diluted 1 þ 4 v/v with 0.125%
Triton X-100, 2.5% HNO3 and 0.31% NH4H2PO4. Compromise pyrolysis and atomisation temperatures for quantitative
determination of the two elements were 500 1C and 1800 1C,
respectively. The use of an end-capped tube improved analytical sensitivities for Cd and Pb by 14% and 25%, respectively,
giving reported LODs of 0.03 mg l1 for Cd and 0.57 mg l1 for
Pb. Results from the analysis of a urine CRM were in good
agreement with the certified value.
Anthemidis and colleagues13 developed a synchronised online solvent extraction and pre-concentration system coupled
with ETAAS for the determination of Cd in natural waters and
urine. The Cd in the aqueous sample was chelated with
ammonium diethyldithiophosphate and extracted with IBMK
using a novel gravitational phase separator. An enrichment
factor of 24.6 was reported giving an LOD of 2.8 ng l1. The
sampling frequency was 30 h1.
1.7.6 Calcium. Many previous methods for the quantitative
determination of Ca in human serum using ICP-MS have
employed oxalate precipitation of Ca from the protein matrix.
The reported problem with this approach is the requirement
for at least 500 ml of serum. To overcome this potential
problem, Chen et al.102 described a simple acid equilibration
procedure in which a 20 ml serum sample was mixed with 2 ml
of HNO3 and equilibrated at room temperature. The 42Ca :
43
Ca ratio in the supernatant was quantitatively determined
using magnetic sector ICP-MS. The authors established the
optimum acid concentration and equilibration time for accurate determination of Ca isotope ratios. The 42Ca : 43Ca ratio
results obtained using this method for serum samples obtained
from healthy volunteers administered enriched 42Ca were consistent with results obtained from oxalate precipitated serum
samples.
1.7.7 Chromium. Cordero and colleagues12 developed a
novel laboratory-built system for the on-line pre-concentration
and speciation of Cr in natural waters and urine prior to
quantitative determination using ETAAS. The autosampler
tip was replaced with two microcolumns packed with chelating
or ion-exchange resin. Control of the rotary valve, for switching columns, and the peristaltic pump were automated with an
electronic control device. Using a 60 s pre-concentration time,
with a sample flow rate of 2 ml min1, and a 40 ml eluent
injection volume, the enrichment factors were 7.4 for CrIII and
5.6 for CrVI. The reported LODs were 0.14 mg g1 for CrIII and
0.08 mg g1 for CrVI.
1.7.8 Cobalt. Methods employing the cloud point precipitation phenomenon continue to be described for pre-concentration of trace elements for quantitative determination by AAS.
Nascentes and Arruda10 described a mixed micelle extraction
method in which Co was complexed with a pyridylazo compound in an aqueous Triton X-100–SDS solution and subsequently extracted into the surfactant-rich phase after phase
separation by addition of HCl or NaCl. The Co concentration
in this surfactant rich phase was determined using FAAS.
Recoveries from spiked solutions were 98–102%. With HCl
as the phase separating electrolyte the reported LOD was 1.1
mg l1, whilst with NaCl the LOD was 1.6 mg l1. The method
was used to determine Co concentrations in pharmaceutical
preparations.
Gopikrishna et al.9 described a method for the quantitative
determination of Co and Ni in hair samples using FAAS. To
eliminate matrix interferences and improve analytical sensitivity, the elements were extracted and pre-concentrated from the
hair matrix by complexation with ethyl xanthate on benzophenone at pH 8–10. The solid complexes were dissolved in 5 ml of
DMF and the solution introduced into the nebuliser of the
flame spectrometer for determination of Co and Ni. The
method was validated by analysis of two hair CRMs and the
results obtained were in good agreement with the certified
values. The method was used by the authors to examine Co
and Ni concentrations in hair samples from inhabitants of
different Indian states.
Following on from earlier volunteer studies demonstrating
skin absorption of Co powder, Filon and colleagues103 described findings from an interesting series of experiments to
investigate the mechanisms for in vitro percutaneous absorption of Co. Skin permeation was calculated using the Franz
331
diffusion cell method with the Co powder suspended in a
synthetic sweat solution and a physiological solution as the
receptor phase. Concentrations of Co in the receptor solution
were determined using ETAAS, whilst ionic Co21 in both
donor and receptor phases was determined using differentialpulse polarography. The researchers calculated a steady state
permeation rate of 0.0123 mg cm2 h1 with a lag time of
1.55 h. They concluded that Co powder was oxidised in the
sweat solution and that the Co21 ions readily permeated across
the skin.
Brodner et al.104 reported findings of a study of serum Co
levels in patients one to five years after metal-on-metal total hip
arthoplasty. Serum Co levels were determined using AAS.
Median serum Co levels were 1 mg l1 one year following
surgery and fell marginally to 0.7 mg l1 after 5 years. The
researchers concluded that there was systematic release of Co
from metal-on-metal articulation throughout the study period
but concentrations remained in a constant range and did not
reflect a run-in wear period for such articulations. Faccioni
et al.105 investigated in vivo metal release from fixed orthodontic appliances. Mucosal cells were collected from the cheeks of
orthodontic patients and control subjects and the cellular
concentrations of Co and Ni quantitatively determined using
ICP-MS. Intracellular concentrations of Co and Ni were 2.4fold and 3.8-fold higher, respectively, in orthodontic patients
compared with controls. Cell viability was lower and DNA
damage, as assessed by the alkali comet assay, was higher in the
orthodontic patients. Significant positive correlations were
found between cellular Co and Ni levels and the number of
comet cells. The authors hypothesised that the release of Co
and Ni from orthodontic appliances could induce DNA
damage in oral mucosa cells.
1.7.9 Copper. Shamsipur et al.8 described a rapid and simple
method for the determination of ultra-trace concentrations of
Cu in aqueous biological samples using AAS. Copper was
quantitatively and selectively extracted from aqueous samples
and digests by adsorption onto a C18 membrane disk modified
with a novel anthraquinone derivative. The adsorbed Cu was
then eluted with a minimal volume of HNO3. An enrichment
factor of 400 was reported giving an LOD of 100 ng l1. The
method was validated by analysing a number of biological
CRMs. Determination of the ratio of free and protein-bound
serum Cu is one of a number of preliminary tests for diagnosis of
Wilson’s disease. Bohrer and colleagues106 compared two
alternative approaches for the determination of free and
protein-bound serum Cu. One approach used a small column
packed with polyethylene powder for the solid-phase extraction of protein-bound Cu. Satisfactory adsorption and elution
were achieved using Mg(NO3)2 as carrier solution and CH3OH
as eluent. Copper in the column effluent (unbound fraction)
and eluate (protein-bound fraction) were quantitatively determined using ETAAS. The second method employed simple
ultra-filtration with a 20 kDa cut-off. Total plasma Cu and
ultra-filtrate Cu concentrations were determined and the protein-bound fraction calculated by simple subtraction of ultrafiltrate Cu from total Cu. Analysis of serum samples from 10
individuals gave comparable results using the two approaches.
With the growing accessibility of multi-element spectrometric techniques, researchers are focusing more on combinations of elements rather than single element studies. Kindness
et al.37 examined the application of LA-ICP-MS for 2D
mapping of Cu and Zn in liver. Line scans and 2D maps of
thin sections of sheep liver revealed zoning of Cu in the tissue.
The authors concluded that the precision of the ablation
method was sufficient to identify non-uniform distributions
and changes in elemental concentrations in tissue sections.
The involvement of Cu and other transition metals in a
range of diseases has been investigated and discussed in this
332
review period. Stadler et al.30 examined the controversial
involvement of transition elements in atherosclerosis. The
researchers employed minimally invasive techniques to avoid
disruption of metal–protein interactions. EPR spectroscopy
and ICP-MS were used to quantitatively determine Cu and Fe
in ex vivo healthy human arteries and carotid lesions. They
determined significantly elevated levels of both Cu (7.5 pmol
mg1 versus 2 pmol mg1) and Fe (0.53 nmol mg1 versus 0.17
nmol mg1) in lesions compared with healthy tissue. Topuzoglu et al.107 compared the concentrations of Cu, Mg and Zn in
serum samples from patients with dilated cardiomyopathy
using AAS. They observed that patients with the disease had
raised serum Cu levels and lower serum Zn levels compared
with healthy controls but found no significant differences in
serum Mg between the two groups. Domellof et al.108 investigated the relationship between maternal mineral status and the
concentrations of Cu and Zn in human milk. Concentrations
of the elements in plasma and milk samples collected from
Honduran and Swedish women were quantitatively determined
using AAS. Mean milk concentrations of Cu and Zn were
higher in Honduran women compared with Swedish women
(0.16 mg l1 versus 0.12 mg l1 for Cu and 0.7 mg l1 versus
0.46 mg l1 for Zn). Milk Cu and Zn concentrations were not
significantly correlated with maternal plasma concentrations of
the elements and the authors concluded that milk concentrations of the elements are not associated with maternal mineral
status, indicating an active transport mechanism in the mammary gland for these elements.
1.7.10 Gadolinium. Neutron capture therapy (NCT) with
Gd for the treatment of certain brain tumours has recently
gained some attention. Smith and colleagues40 used SIMS ion
microscopy to undertake subcellular imaging of 157Gd in a
human glioblastoma cell line incubated with 25 mg ml1 Gd–
DTPA, an MRI contrast enhancing agent. The researchers
determined the intracellular distribution of 157Gd and the six
other naturally occurring Gd isotopes. Gadolinium was heterogeneously distributed in the cells and nuclear Gd was
significantly lower than cytosolic Gd. They considered that
SIMS offered an important role in the development and
validation of Gd containing NCT drugs and new MRI imaging
agents.
157
1.7.11 Gold. Higginbotham and colleagues109 investigated
the tolerance and pharmacokinetics of a novel chemotherapeutic
agent tetrakis(trishydroxymethyl)phosphinegold(I) chloride
(MU-Gold) in dogs. Levels of Au in the serum of dogs
administered MU-Gold (10 mg kg1) intravenously were determined using AAS. Serum Au levels between 10 and 50 mg
ml1 were determined with no observed clinical toxicities. A
two-compartment model with elimination half-life of 40 h and
mean volume of distribution of 0.66 kg was developed to
describe the pharmacokinetics of the compound.
1.7.12 Iron. Ohno et al.110 determined 56Fe : 54Fe and
Fe : 54Fe isotope ratios in human erythrocytes using multicollector ICP-MS. To eliminate non-mass spectrometric interferences on the measured ratios, the Fe ions were separated from
the organic matrix and major elements using ion chromatography. The ArO and ArOH interferences on the 56Fe and 57Fe
isotopes were minimised by operating a dry plasma with a
desolvation nebulizer for sample introduction. The precision of
the ratio measurements was sufficient to monitor natural
variations in Fe isotope ratios. The authors used the method
to examine the seasonal variation of Fe isotope ratios in
human volunteers over 12 months. They reported no significant seasonal changes in Fe ratios, which they hypothesised
was due to the small contribution of daily Fe intake (1 mg) on
the total body content of Fe (2–4 g). They did note, however,
57
that Fe isotope ratios in the female volunteer were different
from the mean of the male volunteers, which they hypothesised
may be due to differences in the efficiency of Fe uptake from
the diet. Jin111 also described work on the determination of Fe
isotope ratios using ICP-MS for iron nutritional studies. This
researcher used double focusing ICP-MS to determine 54Fe :
56
Fe, 57Fe : 56Fe and 58Fe : 56Fe isotope ratios in food
samples and human faeces. Argon oxide interferences on the
54
Fe and 56Fe masses were overcome by operating the instrument in a high resolution mode.
Several studies have examined Fe status in patients with
various diseases. Leveque and colleagues112 examined levels of
Fe and ascorbic acid in dermis from healthy individuals and
individuals with psoriasis. The Fe and ascorbic acid concentrations were determined in micro-dialysates from healthy and
psoriatic dermis using AAS and GC-MS, respectively. Levels
of Fe in ‘involved’ psoriatic dermis (57 mg l1) and ‘uninvolved’
psoriatic dermis (49 mg l1) were significantly higher than in
healthy dermis (21.8 mg l1), whilst ascorbic acid levels in both
psoriatic tissue types were significantly lower than in healthy
dermis. Kucharzewski et al.113 investigated Fe levels in serum
and tissue of patients with colorectal cancer, patients with
colon and rectal polyps and healthy individuals. Serum and
tissue Fe levels were determined using TXRF. The mean serum
Fe level in colorectal cancer patients was significantly lower
(54.5 mg g1) compared with patients with polyps (91.3 mg g1)
and control subjects (108 mg g1), a pattern that was also
reflected by serum ferritin but not by albumin or haemoglobin.
Finally, in studies to examine the potential role of Fe species in
Parkinson’s disease, Ide-Ektessabi et al.45 examined the distribution of Fe in the substantia nigra region of the brain of
monkeys injected with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. Elemental mapping was performed using SR-XRF
and X-ray absorption near edge structure (XANES). Powders
of FeO (Fe21) and Fe2O3 (Fe31) were used as reference
samples for XANES measurements. The researchers noted
that cells with a high Fe content had high levels of Fe21 ions
and hypothesised that the greater potential for this species to
generate free radicals may be a contributory factor to oxidative
stress and cell death.
1.7.13 Lead. Reported studies on Pb have declined significantly in this review period as more attention is focused on
multi-element studies. The introduction of standards and guidelines on uncertainty estimates for analytical measurements has
resulted in more attention being paid by laboratories to the
calculation and reporting of uncertainty with their analytical
results. Patriarca and colleagues114 published a comprehensive
and informative working example for estimation of uncertainty
of blood Pb determination using ETAAS, based on the EURACHEM/CITAC guidelines. Blood samples were diluted 1 þ 1
v/v with 0.2% Triton-X100 and injected with NH4H2PO4 (5 g
l1) and Mg(NO3)2 (0.5 g l1) chemical modifiers. Matrix
matched standards were used for calibration. Trueness of
analytical results was assessed by analysis of CRMs and by
comparison with target values for other blood reference materials. The expanded uncertainty for blood Pb measurements
ranged from 16% to 20% depending on the blood Pb concentration.
Groups continue to investigate alternatives to venous blood
samples for the biological monitoring of occupational Pb
exposure but still reach the same conclusions as pioneering
researchers over 30 years ago. Taylor et al.115 examined the use
of capillary earlobe blood samples for biological monitoring of
Pb. Both earlobe and venous blood samples were taken from
exposed workers and the Pb concentrations determined using
ETAAS. A mean difference of 38 mg dl1 was found between
earlobe and venous blood samples taken from the same
individual and more than 50% of earlobe samples had Pb
levels more than twice the level in the corresponding venous
sample. These enormous differences clearly highlight the contamination risks associated with biological monitoring if sampling is not appropriately controlled. The authors reported
that 54% of workers surveyed preferred earlobe sampling.
However, considering the biological monitoring action level
for blood lead is between 50 mg dl1 and 70 mg dl1 for many
countries, it would be interesting to note what the response
might be if told that earlobe sampling gave a 50% chance of a
false result which might lead to suspension from work. The
authors rightly concluded that earlobe sampling was still not
appropriate for biological monitoring of Pb exposure.
Studies continue to examine body burdens of Pb and the
monitoring of continuing falls in environmental Pb exposures.
The well recognised relationship between body Fe burden and
Pb absorption led Wright and colleagues116 to investigate
whether the haemochromatosis genotypes C282Y or H63D
(HFE variants) were associated with body Pb burden in elderly
men. Volunteers from a national ageing study were genotyped
for the two HFE variants and patella and tibia Pb levels
determined using K-XRF. Multivariate linear regression models were constructed to adjust for age, smoking and education.
The adjusted data showed that elderly men with the HFE
variants had lower patella Pb levels and suggested that alterations in Pb toxicokinetics may be mediated by Fe metabolic
pathways regulated by HFE gene products. Dorea117 produced
a comprehensive review on environmental exposure to Hg and
Pb and the transfer of these elements from mother to foetus
and infant. The review concluded that diets consumed by
lactating mothers pose no significant health hazards to
breast-fed infants but that formula feeds based on cow’s milk
posed a greater risk of infant exposure. Ettinger et al.118 also
investigated the relationship between maternal bone Pb stores
and concentrations of Pb in human milk through a large scale
study of women in Mexico City. The concentrations of Pb in
umbilical and maternal blood were determined in 310 women
at the time of delivery. Subsequently, levels of Pb in human
milk, blood and patella and tibia bone were determined in the
same women one month post-partum. Levels of Pb in human
milk ranged from 0.21 to 8.02 mg l1 (geometric mean 1.1 mg
l1) and blood Pb levels ranged from 1.8 to 29.9 mg dl1
(geometric mean 8.4 mg dl1). The researchers determined
statistically significant relationships between human milk Pb
and umbilical Pb, with maternal blood Pb at delivery and one
month post partum and with patella Pb. However, maternal
age, length of residence in Mexico City and use of lead glazed
ceramics were not significant predictors of human milk Pb.
They estimated that a 5 mg dl1 increase in maternal blood Pb
was associated with a 33% increase in human milk Pb and that
a 20 mg g1 increase in patella Pb with a 14% increase in
human milk Pb. They concluded that human milk Pb levels
were influenced by both current and past Pb exposure. Martinez et al.59 determined blood Pb levels in a randomly sampled
population from the Mexico Valley. Blood samples were acid
digested and Fe extracted with IBMK to improve the analytical sensitivity for determination of Pb using TXRF. The
authors reported a mean blood Pb level of 2 mg dl1 compared
with a mean value of 22 mg dl1 determined for a similar
population in 1980. Soldin and colleagues119 also reported a
significant decline in blood Pb levels in a large paediatric
population from the Washington DC area. A median blood
Pb level of 3.3 mg dl1 was reported which was significantly
lower than levels determined for a similar population in 1991.
There is significant supporting data from other studies to show
that these are genuine declines in environmental exposure
rather than improvements in analytical techniques.
Finally, two groups described methods to determine the Pb
content of tooth enamel. Uryu et al.38 determined the Pb : Ca
ratio in the enamel of deciduous teeth using LA-ICP-MS. A
pelletised bone CRM was used as a single point calibrant and
333
the reported LOD was 11 mg kg1. The authors considered the
method to be of value for the assessment of in utero Pb
exposure. Gomes et al.120 took superficial enamel biopsies
from deciduous teeth for quantitative determination of Pb
using ETAAS. The enamel biopsies were taken from four to
five year olds living in industrial and suburban areas of
Piracicaba City, Brazil. The researchers established that biopsy
depths greater than 3.9 mm gave the most reproducible results.
Enamel Pb concentrations in children from industrial areas
(169 mg g1) were significantly higher than those from children
in non-industrial areas (118 mg g1).
1.7.14 Lithium. The narrow therapeutic range of Li for
treatment of depressive disorders requires regular monitoring
of plasma Li levels in patients on such medication. To test the
hypothesis that the Li concentration in erythrocytes is a better
indicator of brain Li levels, Camus et al.121 compared Li
concentrations in plasma, erythrocytes and the calculated ratio
(LiR) in patients classified into three groups: therapeutic drug
monitoring, acute intoxication and acute-on-chronic intoxication. Plasma and erythrocyte Li concentrations were determined using AAS. The researchers found a good correlation
between plasma and erythrocyte Li concentrations (r ¼ 0.81).
They also reported that plasma Li was more elevated in cases
of acute intoxication whilst Li accumulated preferentially in
erythrocytes in acute-on-chronic intoxication. They concluded
that measurement of both plasma and erythrocyte Li and the
calculated ration LiR may be sensitive markers of Li intoxication.
1.7.15 Magnesium. Bohn and colleagues122 investigated the
merits of determining Mg in urine and erythrocytes to monitor
Mg absorption as alternatives to the conventional method of
faecal Mg measurement. Ten volunteers were given 2.2 nmol of
25
Mg in water, together with bread, followed by an i.v. injection of 0.6 nmol 26Mg. Urine and faeces were collected for 6
days and a blood sample taken on day 14 following administration of the Mg isotopes. Isotope ratios were determined in
urine and faecal samples using TIMS and in erythrocytes using
ICP-MS. Determination of Mg absorption was based on either
six day or 24 h urine pools, six day faecal pools or a single
blood sample taken 14 days after intake of Mg isotopes. The
researchers found no significant differences in the mean Mg
absorption (42%) determined by the different measurement
approaches except when based on a six day urine pool, when
the calculated absorption figure was 33%. They concluded that
Mg absorption can be accurately determined from 24 h pooled
urine samples or a single blood sample as alternatives to faecal
monitoring.
1.7.16 Manganese. Speciation of Mn in human milk was
comprehensively studied by Michalke and Schramel123 using
both ICP-AES and ICP-MS. In a preliminary investigation,
human milk was centrifuged and the Mn content of the
supernatant and pelleted fraction determined using ICP-AES.
The total concentration of Mn in the defatted milk fraction
was 2.85 mg l1 and the Mn concentrations in the low Mr
supernatant and pelleted fractions were 2.6 mg l1 and 0.25 mg
l1, respectively. The defatted milk fraction was further investigated by on-line coupling of SEC and anion exchange
chromatography to ICP-MS. Manganese was predominantly
associated with low Mr species, with masses around 300 Da.
Inorganic Mn and Mn–citrate complexes were positively identified. Other low Mr species were found but could not be
characterised.
Whilst studies show increased risks of pneumoconiosis and
other respiratory diseases related to exposures to welding fumes,
manganism resulting from exposure to welding fume is still
something of a controversial issue. Yu et al.124 investigated the
334
distribution of Mn in brain tissue of rats exposed to welding
fumes generated from manual metal-arc stainless steel. Rats
were exposed to fumes containing either 1.6 mg m3 Mn or 3.5
mg m3 Mn for 2 h per day over a 60-day period. Concentrations of Mn in blood, brain, lung and liver were determined
using AAS. Dose and time dependent increases in liver and
lung Mn were reported but only slight increases in blood Mn
were observed. Statistically significant increases in the Mn
content of brain cerebellum were also reported together with
slight increases in Mn concentrations in the substantia nigra
and basal, temporal and frontal cortex. The authors concluded
that the tissue distribution of Mn derived from welding fume
was different from that resulting from dietary manganese
exposures.
1.7.17 Mercury. The contribution of dental amalgam to an
individuals Hg body burden continues to be investigated. Two
groups examined exposure to Hg from amalgam fillings. Halbach and Welz125 described a novel method for the real-time
direct determination of Hg in intra oral vapour using AAS with
Zeeman effect background correction. Intra oral air was aspirated through a disposable mouthpiece and pumped to the
spectrometer using computer-controlled valves and a programmable timer. The researchers adapted the system to investigate
the emission of Hg from amalgam in situ and from amalgam
samples in vitro. A series of measurements on an individual
volunteer gave a coefficient of variation between 18% and 25%
and the method was sufficiently sensitive to measure a significant increase in the emission of Hg following insertion of new
fillings. Hansen et al.126 developed a standardised procedure
for evaluating the Hg exposure of individuals with amalgam
fillings and monitored over 2000 patients to establish a reference database to act as a diagnostic tool. The researchers
quantitatively determined Hg in scalp hair and urine, before
and after administration of dimercaptopropane sulfonate
(DMPS), using AAS. Release of Hg from dental amalgam
was monitored by a chew test with quantitative determination
of Hg in the chewing gum. The reported 50th percentiles were
1.3 mg g1 creatinine in basal urine, 32 mg g1 creatinine after
administration of DMPS and 454 ng g1 in hair. The measured
concentrations in the chewing gum were reported to correspond to a release of 1 mg Hg per minute of chewing.
Several groups have described methods for the determination of total Hg in different biological matrices. Anthemidis
et al.21 developed a method for the determination of trace
levels of Hg in a variety of biological matrices using on-line
micro-column pre-concentration coupled with CV-ICP-AES.
Mercury in acid digested samples was complexed with APDC
and adsorbed onto fine PTFE turnings packed in the lower
compartment of a combined pre-concentration column and
gas–liquid separator. The mercury was subsequently released
from the PTFE as vapour by reduction with SnCl2 and
pumped directly from the gas–liquid separator into the plasma.
Using a 60 s pre-concentration step, the authors reported an
LOD of 0.01 mg l1. The method was validated by analysing a
marine CRM (BCR CRM 278). Barbosa et al.349 described an
improved method for the determination of Hg in whole blood,
which eliminated on-line microwave digestion and overcame
the problem of protein precipitation and resulting high back
pressure associated with this approach. Blood samples (300 ml)
were mixed with an equal volume of 10% TMAH and incubated at room temperature for one hour. The samples were
further diluted 1 þ 4 v/v with 2% HCl for quantitative
determination using FI-CV-AAS. The method was validated
by analysing whole blood CRMs and samples from a proficiency testing scheme. The reported LOD was 0.2 mg l1.
Methods for the quantitative determination of methylmercury in biological matrices were described by two research
groups. Chen et al.127 determined methylmercury in fish tissue
using GC-MS, following derivatisation of the methylmercury
with Cu21 and sodium tetrapropylborate. Tissue samples were
microwave digested with alkaline TMAH for derivatisation of
Hg and extraction into n-heptane. The extracted derivative was
injected and adsorbed in the splitless injection port of the gas
chromatograph. The method was validated by analysing three
marine tissue CRMs and the results obtained were in good
agreement with the certified values. Montuori et al.128 established the optimised digestion conditions for human hair
samples in order to minimise the degradation of methylmercury prior to aqueous phase ethylation and quantitative determination of methylmercury using GC-CVAFS. Clough and
colleagues129 determined the concentrations of inorganic Hg
and methylmercury in two CRMs using ID-SF-ICP-MS for
quantitative determination of the mass fraction of Hg in NIST
2710 and HPLC coupled with ID-ICP-MS for quantitative
determination of the mass fraction of methylmercury in
DORM-2. The researchers examined the temporal equilibration of the ID spike by monitoring the 200Hg : 199Hg ratio.
Complete equilibration in the NIST CRM was only achieved
with microwave digestion using 10% HNO3. For the DORM-2
CRM, complete equilibration was achieved with a 50 : 50
H2O : CH3OH solvent containing 0.01% mercaptoethanol.
The researchers also calculated uncertainty budgets for each of
the quantitative determinations. Morrissette et al.79 studied the
temporal variations of blood and hair Hg concentrations in
pregnant women living along the St. Lawrence river. The
authors recruited 159 pregnant volunteers, who completed
detailed questionnaires on fish consumption before and during
pregnancy. Blood samples were taken in the three trimester
periods and a further blood and hair sample taken at the time
of delivery. Blood Hg was determined using CVAAS and hair
Hg using CVAFS. Both blood and hair Hg levels increased
during the second and third trimester. Cord blood Hg was
higher than maternal blood Hg at birth and a strong correlation was observed between the frequency of fish consumption
and Hg concentrations in mothers and their newborn. Multivariate analysis showed that market and frozen fish was a more
important contributor to body burden of Hg than local fish
from the St Lawrence river.
1.7.18 Molybdenum. Turnlund and Keyes130 investigated the
effect of dietary Mo intake on plasma Mo levels using ICP-MS.
Twelve male volunteers were put on a low Mo (22 mg d1) diet
for 24 days, after which they were divided into different study
groups and administered different regimes of low and high
daily dietary Mo intake. During the intial 24 day period on low
Mo intake, the mean plasma Mo concentration fell from 8.2
nmol l1 to 5.1 nmol l1 at day 24. Subsequently the plasma
Mo concentration reflected the low and high dietary intake
within 14 days of a change in Mo intake. The study was
performed so as to obtain data, from which, dietary intake
recommendations could be made.
1.7.19 Nickel. The speciation of Ni in tissue extracts from
healthy and cancerous colon tissue was investigated by Bouyssiere and colleagues.131 Sequential anion exchange chromatography and SEC, coupled with SF-ICP-MS, resolved and
quantitatively determined several nickel-binding biomolecules
from the tissue extracts. No significant differences in the
pattern of Ni species were found between the cancerous and
normal tissue.
A similar study to that described earlier in the section on
cobalt was undertaken by Eliades et al.132 who investigated the
cytotoxicity of ions released from nickel–titanium and stainless
steel orthodontic alloys. Full sets of stainless steel orthodontic
brackets and nickel–titanium wires were incubated in 0.9%
saline for one month. Concentrations of elemental ions released into the incubation solution were quantitatively deter-
mined using ICP-MS. Cytotoxicity of the incubation medium
was assessed using periodontal and gingival fibroblasts. No
measurable release of ions was observed with the nickel–
titanium wires, but Cr and Ni were quantitatively determined
in the stainless steel incubation medium. Neither of the two
incubation media had any cytotoxic effect on the fibroblast
cell lines.
1.7.20 Phosphorus. Innovative uses of DRC-ICP-MS have
been published in this review period. Bandura et al.133 determined P and S, as PO1 and SO1, in cell culture digests using
ICP-DRC-MS with O2 as the reaction gas in the DRC. The
reported sensitivity allowed the determination of pmol ml1
concentrations of phospho-proteins using S as an internal
standard. The method was used to examine P : S ratios in cell
cultures from malignant and non-malignant cell lines. The
researchers reported that the PO1 : SO1 ratio in human
colorectal adenocarcinoma cells was 1.75 times higher than
in normal tissue from the same patient. In the same paper, the
researchers described the quantitative determination of the
phospho-protein phosvitin at nanomolar levels in 1D polyacrylamide gels using LA-ICP-MS.
Becker et al.36 also used LA-ICP-MS to determine P, S and
metal elements in human brain proteins separated by 2D gel
electrophoresis. Quantitative determination of the elements in
single protein spots was achieved using a SF-ICP-mass spectrometer.
1.7.21 Platinum and noble metals. In previous ASU reviews,
the large proportion of papers on the determination of Pt in
biological matrices has been related to studies on Pt based anticancer drugs. This review period has seen growing interest in the
assessment of environmental exposures to platinum group elements (PGEs). Zaray and colleagues134 determined Pt in urine
samples collected from 100 adults living in the city centres of
Budapest and Vienna. Urine samples were simply diluted 1 þ 9
v/v with distilled H2O for quantitative determination of Pt
using HR-ICP-MS. Particulate air samples were also collected
from the two city centres. The polycarbonate filters were acid
digested in a microwave digestion system for determination of
Pt, also using high resolution ICP-MS. Mean concentrations of
Pt in residents of Budapest were about three times greater than
levels in the Vienna residents. This difference was reflected in
the concentrations of Pt in the respirable fraction of the aerosol
samples collected from the two city centres. Bocca et al.135
presented the findings of a comprehensive study of environmental exposure to platinum group elements (PGEs) in the
Italian population. Urine samples were collected from 257
adult residents from two representative cities, one a small
urban environment characterised by low traffic density (Foligno) the other a large city with constant high traffic density
(Rome). Urine samples were diluted 1 þ 4 v/v and PGEs
determined using SF-ICP-MS. The researchers found significant differences in the concentrations of Pt and Rh between the
two populations. The ranges of urine Pt and Rh levels in the
Foligno population were 0.24 to 3.08 ng l1 and 0.53 to 14.8 ng
l1, respectively, compared with ranges of 0.49 to 8.31 ng l1
for Pt and 4.1 to 38.6 ng l1 for Rh in the Rome population.
The same group of researchers136 monitored exposure to airborne Pt in traffic officers from the Rome City police force.
Urine samples were collected from 103 traffic officers and a
control group of 58 office workers. Urine concentrations of Pt
were quantitatively determined using SF-ICP-MS. Although
the Pt concentrations determined were higher than values
reported for other urban populations, the researchers found
no difference in urine Pt levels between the traffic officers (4.45
ng l1) and the office workers (4.56 ng l1).
Bettinelli et al.137 presented a method for the quantitative
determination of Pt in biological fluids using ICP-MS in which
335
the analytical uncertainty for Pt determination in different
matrices was assessed using the EURACHEM/CITAC guidelines. The researchers reported LOQs of 1 mg l1 for plasma,
0.1 mg l1 for plasma ultra-filtrate and 2 mg l1 for urine
matrices. They argued that the estimation of uncertainty of
measurements of Pt in clinical samples had important implications when used to interpret the pharmacokinetics and optimised therapy regimes for Pt anticancer agents. Fan and
colleagues138 described a novel method for the quantitative
determination of PGEs in biological and environmental samples using ETV-ICP-MS. The elements were separated from
the sample matrix by chelation with DDC. Using a low
vaporisation temperature of 1100 1C, PdII, PtII and RhIII were
introduced into the plasma as the gaseous dithiocarbamate
complexes. With optimised conditions for complexation and
thermal treatment, the authors reported LODs of 1.4 ng ml1,
5.4 ng ml1 and 0.8 ng ml1 for Pd, Pt and Rh, respectively.
Zimmermann et al.139 evaluated a method for the quantitative
determination of ultra-trace concentrations of PGEs in small
quantities of biological tissue using ETAAS following microwave digestion of the tissue samples. Tissue samples were
obtained from mussels experimentally exposed to PGE salts
and ground automobile catalytic converter material. Reported
LODs ranged from 13 ng g1 for Rh to 270 ng g1 for Pt. The
authors compared this method with reference methods using
high pressure ashing and CSV for Pt and Rh and TXRF after
co-precipitation with mercury for Pd. They concluded that
ETAAS was sufficiently sensitive for routine analysis of tissue
samples with concentrations of PGEs in the upper ng g1
range.
Several groups have described pharmacokinetic studies on
platinum based anticancer drugs. Hann and colleagues140
determined cisplatin and its degradation products mono- and
di-aquacisplatin in aqueous solutions and urine samples using
HPLC coupled with ICP-MS. The researchers established the
degredation kinetics of cisplatin in aqueous solutions of different Cl concentrations. They reported that no equilibration
was established between cisplatin and its products, which
decayed after several hours. The urine samples contained a
large fraction of mono-aquacisplatin and several uncharacterised Pt species. Warren et al.141 determined the pharmacokinetics of carboplatin when administered in combination with
lobradimil to paediatric patients with brain tumours. Carboplatin was administered at a dose rate to achieve target areaunder-the curve (AUC) concentrations of 3.5 mg min ml1.
Plasma ultrafiltrate Pt was determined using AAS and the
AUC derived. The authors observed that the measured AUC
exceeded the target AUC in all patients by a median value of
35%, and they concluded that the failure of adaptive dosage of
carboplatin with lobradimil to meet the target AUC concentration was due to an unexpected drug interaction. Ghezzi
et al.142 investigated the intracellular uptake and accumulation
of Pt in a breast cancer cell line (MCF-7) using ICP-MS.
Cultured cells were incubated with cisplatin, carboplatin and
oxaliplatin. The results led the authors to hypothesise a passive
diffusion mechanism for cellular uptake. Hagrman and colleagues143 studied the binding of Pt drugs to glutathione in
conditions mimicking the cell cytosol. The reactions were
monitored by UV spectroscopy and HPLC coupled with
AAS. The authors derived first order reaction kinetics for
different Pt compounds, noting that the reaction of carboplatin
with GSH was 32 times slower than for oxaliplatin and 23
times slower than that for cisplatin.
1.7.22 Selenium. Different sample preparation methods for
the determination of Se in plasma using magnetic sector ICP-MS
were examined by Featherstone and colleagues.144 The authors
reported the most suitable method to be a 1 þ 9 v/v dilution of
plasma using 0.5% v/v CH3CH2OH with an internal standard
336
of In or Sc. Interference from 40Ar37Cl precluded the quantitative determination of Se based on the measurement of 77Se in
low resolution mode and reliable results were only achieved
with measurement of the 82Se isotope in high resolution mode.
The authors used the method to determine Se in plasma
samples from a healthy population and a mean plasma Se
concentration of 102 mg l1 was reported. The stability of Se in
plasma samples was investigated by Sabe et al.145 The authors
compared two calibration methods: matrix matching and
standard additions. They found significant differences in the
measured plasma Se concentrations using the two calibration
procedures. They established that plasma Se levels remained
stable for up to one year when stored at 20 1C. Mazej et al.146
determined Se in human milk using HGAFS. Satisfactory
digestion of the sample matrix was achieved with H2SO4–
HNO3–H2O2 and the method was sufficiently sensitive for
quantitative determination of Se in a 1 ml sample volume.
An LOD of 0.25 ng g1 was reported and a mean Se concentration of 12 ng g1 was found in milk samples from healthy
lactating women in North Eastern Italy. The same group147
also used HGAFS to determine Se in digests of water soluble
proteins and peptides. Protein solutions were digested with
HNO3–H2O2 and an LOD of 0.2 ng g1 was reported. Chery
et al.35 presented a comprehensive and systematic study on the
quantitative determination of metalloproteins using LA-ICPMS, following separation of proteins by polyacrylamide gel
electrophoresis (PAGE). The researchers used this approach to
determine yeast extract selenoproteins separated by 2D PAGE
and selenoproteins from erythrocyte extracts after 1D separation by PAGE. The use of a DRC with CO or He as reaction
gas eliminated interferences on the most abundant 80Se isotope
and gave reported LODs of 0.07 mg g1 for single hole ablation
and 0.15 mg g1 for translational ablation.
In common with recent past reviews, much of the work on Se
this period has focused on Se speciation. Huerta et al.148
described two sample preparation methods for the characterisation of Se species in urine using ES-MS-MS. The selenocompounds were separated from the urine matrix and preconcentrated by sequential steps of SEC, reversed-phase
HPLC and freeze-drying. The authors used the method to
characterise Se-methyl-N-selenohexosamine in urine from rats
administered selenomethionine.
Gammelgaard and Bendahl149 separated ten Se species from
urine samples collected from two volunteers consuming selenised yeast. Urine samples were pre-concentrated up to 100fold by evaporation under N2 and CH3OH extraction. The Se
species were separated by reversed-phase and ion-pair chromatography for quantitative determination using ICP-MS.
Eluent from the chromatograph was introduced into the
plasma through a micro-concentric nebuliser or DIN, for
samples with high concentrations of dissolved solids. Only
two Se species were characterised. The major urine species
was Se-methylacetylgalactosamine, whilst Se-methyl-N-acetylglucosamine was a minor constituent present at a concentration less than 2% of the acetylgalactosamine species. In a
subsequent report,150 the same researchers characterised a
third urinary Se metabolite using nano-ES-MS. Basal urine
samples from volunteers not given Se supplements were lyophilised and Se species extracted with CH3OH for separation
and pre-concentration using reversed-phase HPLC and SEC.
In addition to the two Se species reported in the previous
paper, the authors identified Se-methylselenogalactosamine.
This species was present in higher concentrations than Semethyl-N-acetylgalactosamine and led the authors to hypothesise that this may be the main urinary metabolite in basal urine.
Braga and colleagues151 investigated the in vitro reaction of
selenite with plasma thiol compounds glutathione, cysteine and
homocysteine. The reaction products were characterised using
HPLC-ES-MS and quantitatively determined using HPLCICP-MS. The use of a collision cell and H2 reaction gas allowed
selective monitoring of 77Se, 78Se and 80Se masses. The reaction
products were effectively separated on a C8 column with a
mobile phase of 12% CH3OH–0.05% heptafluorobutyric acid
and LODs below 1 mg l1 were reported. The selenotrisulfide
derivatives were also determined in extracts from liver cytosol
extracts from Se exposed rats.
Lipsky et al.83 compared the concentrations of Se in toenails
from a group of patients with recently diagnosed prostate
cancer and a healthy control group. Nails were acid digested
with microwave heating and Se quantitatively determined
using ICP-MS with a DRC. Median concentrations of Se in
toenails in the cancer and control groups were 528 ng g1 and
502 ng g1, respectively. The lack of any significant difference
in nail Se concentrations between the two groups led the
authors to question the protective role of Se for prostate
cancer. Strambi et al.152 compared the Se status of adequatefor-gestational age (AGA) and small-for-gestational age
(SGA) infants in the first months of life. Selenium status was
assessed by quantitative determination of Se in erythrocytes
and plasma using ETAAS. The authors observed lower plasma
Se levels in breast-fed and formula-fed SGA infants compared
with AGA infants. Breast-fed SGA infants had higher plasma
Se levels than formula-fed SGA infants, which led the authors
to caution that Se intake, unless supplemented, is likely to be
inadequate in bottle-fed SGA infants.
1.7.23 Silver. Graham and O’Meara49 investigated the potential of XRF for the in vivo determination of Ag in skin. The
spectrometer used an 125I excitation source, sample and detector arranged in a 901 geometry. With this arrangement, the
analysis of Ag doped skin phantoms indicated an LOQ of 3–4
ppm (3–4 mg g1).
The authors considered the system had sufficient sensitivity
to be considered for non-invasive monitoring of Ag exposed
workers, particularly to identify individuals with increased risk of
exhibiting argyria.
1.7.24 Strontium. Vonderheide et al.153 investigated different
instrumental systems for the determination of 90Sr in urine using
ICP-MS. Quadrupole ICP-MS with a hexapole collision cell
was insufficiently sensitive for the quantitative determination
of 90Sr in the urine matrix. However, double-focusing SF-ICPMS operated with a cool plasma and medium mass resolution
was sufficiently sensitive. Strontium was extracted from the
urine matrix using a crown ether extraction resin, giving an
enrichment factor of 200. An LOD of 0.4 pg l1 was reported
and recovery of 90Sr from spiked urine samples was 82–86%.
1.7.25 Titanium. Titanium prostheses may often be coated
with a biological glass to prevent corrosion. The glass coating
isolates the metal implant from surrounding tissue until the
coating is replaced by new bone after some three months of
implantation. Barbotteau and colleagues48 examined the release of Ti from glass coated metallic prostheses using PIXE.
They observed that after several months of implantation, Ti
concentrations in tissue surrounding the implant were stabilised and restricted to the first tens of micrometres of surrounding bone. Wennerberg et al.154 examined Ti release from
metallic oral implants in both in vitro and in vivo studies using
SRXRF and SIMS. The researchers implanted titanium oral
implants, with different degrees of surface roughness, into
rabbit tibiae. They determined Ti release 12 weeks and one
year after implantation and observed no significant correlation
between the degree of surface roughness and ion release.
1.7.26 Uranides and actinides. Bouvier-Capley et al.155 presented a comprehensive review of the performance of ICP-MS
for the quantitative determination of actinides in urine for
monitoring of exposed populations, which they considered
could be used as a guide for laboratories to select the most
appropriate procedure for their particular investigation.
Whilst in the recent past much of the work on these elements
was related to exposures of Gulf war veterans, interest has now
also focused on exposures in the general population. Gwiazda
et al.156 used HR-ICP-MS to determine U isotope ratios in
urine samples from American Gulf war veterans exposed to
depleted U. The 235U mass was fully resolved with an instrument resolution of 4000. The authors studied three groups of
veterans: exposed soldiers with embedded shrapnel, exposed
soldiers with no embedded shrapnel and a reference group of
deployed soldiers not exposed to depleted U. Urine U concentrations in soldiers with embedded shrapnel were significantly higher than in the other two groups, and 16 of the 17
soldiers monitored had detectable depleted U in their urine. In
exposed soldiers with no embedded shrapnel, depleted U was
determined in urine from 10 of the 28 soldiers studied. The
researchers concluded that assessment of depleted U exposure
must be based on U isotope ratio measurements rather than
total U determinations. Durakovic and colleagues157 also
determined U isotopes in 24 h urine samples collected from
Gulf war veterans. The 238U : 235U ratio was determined using
TIMS. The authors reported urinary U concentrations of
3.27 105 mg per 24 h for exposed veterans and 1.46 108 mg per 24 h in unexposed veterans. They used the
measured urinary concentrations together with calculated dissolution half-times for ceramic depleted uranium oxide to
estimate time zero lung burdens of depleted U. They estimated
that the lung burden of depleted U at time zero could be
accurately determined as late as nine years after initial exposure.
Pappas et al.158 described a rapid method for the direct
determination of 239Pu in urine using magnetic sector ICP-MS
with a desolvating sample introduction system. The 239Pu was
separated from U and potentially interfering polyatomic species in a 1 ml urine sample by solid phase extraction. The
reported LOD was 1.4 fg ml1 in the presence of 1000 ng l1 of
depleted U. The researchers considered the method to be
sufficiently sensitive for emergency exposure assessment. Vanhaecke et al.159 also developed a rapid method the determination of total U concentrations in urine using sector field ICPMS. Urine samples were diluted 1 þ 9 v/v with 0.14 mol l1
HNO3 and calibration was performed with external standards
rather than standard additions or ID to achieve a high sample
throughput for epidemiological studies. The use of Re as an
internal standard and optimised carrier gas flow minimised
matrix interferences on the 238U : 187Re signal ratio. An LOD
of 0.2 ng l1 was reported. The authors used the method to
determine concentrations of U in non-exposed populations
from Belgium and the Netherlands. A typical urinary U
concentration of 3–4 ng l1 was found, though some urinary
U values exceeded 10 ng l1. Finally, Al-Jundi et al.160
examined the influence of age and residential area on urinary
Th and U in a non-exposed Jordanian population. Urine
concentrations of 232Th and 238U were quantitatively determined using ICP-MS. The mean urinary concentration of both
elements was found to be proportional to age up to 60 years
and a noticeable drop in urinary levels was observed in subjects
over 60 years old.
1.7.27 Zinc. Stenberg et al.161 described a detailed study of
the isotopic composition of Zn in different biological matrices
using multi-collector HR-ICP-MS. Sample preparation involved acid digestion followed by anion exchange chromatography. Most interferences were reduced to negligible levels
using a high resolution setting and residual spectral interferences from species such as 35Cl16O2 and 40Ar14N2 were resolved
instrumentally. Only the 35Cl2 interference on 70Zn could not
be eliminated instrumentally and required further sample preJ. Anal. At. Spectrom., 2005, 20, 323–369
337
treatment for accurate quantitative determination of the 70Zn
isotope.
A number of studies examined Zn status and metabolism in
different populations and different clinical conditions. In an
important study, Vartsky et al.52 used XRF to determine Zn
concentrations in prostate tissue samples removed during
surgery. They reported a relationship between prostate tissue
Zn concentrations and corresponding prostate-specific antigen
levels in blood, which gave improved differential diagnosis of
prostate cancer and benign prostate hyperplasia. The authors
considered the combined measurement of these parameters
provided a powerful tool for more accurate diagnosis of
prostate disease and argued for the need to develop the
capability for in vivo determination of Zn in the prostate. Rush
et al.80 evaluated Zn determination in recently grown hair as a
biomarker of current Zn status. The researchers examined
seasonal variation in hair Zn levels in a healthy adult population from New Zealand. Hair samples were taken at monthly
intervals between June and December. The samples were
thoroughly washed and digested with HNO3 for quantitative
determination of Zn using FAAS. No seasonal variation in Zn
levels was found. Tanzer et al.162 investigated the impact of
socioeconomic status on the Zn status of Turkish children and
whether Zn status had any effect on anthropometric parameters. Blood samples were taken from 432 randomly selected
children aged between 7 and 11 years. Each child’s height and
weight were also recorded. Serum Zn concentrations were
determined using AAS. Mean serum Zn concentrations in
children with low and middle socioeconomic status were 56.3
and 86.6 mg dl1, respectively, whilst those in the highest
socioeconomic status had a mean serum Zn concentration of
110.7 mg dl1. A height for age Z-score of 2 or lower was
recorded for 56% of children with a low socioeconomic score
compared with less than 10% of children with a medium or
higher socioeconomic score. Cavdar et al.81 described the
results of a longitudinal study of plasma and hair Zn levels
in pregnant women. Plasma and hair Zn concentrations were
quantitatively determined using AAS. The authors reported
that both hair and plasma Zn declined significantly during the
second trimester of pregnancy. They also noted a significant
difference in plasma Zn levels between well-nourished and
poorly-nourished study groups.
Analyses of clinical and biological materials are recorded
in Table 1.
2 Analysis of drugs and pharmaceuticals, traditional medicines
and supplements
This subject spans the clinical and food topics, particularly
with yeasts and plant-based remedies, which represent an
obvious link between these application areas. In addition to
discussion here, there are entries within both Tables and,
because of the importance of measurements in tissue specimens, in Part 1 within the sections on individual elements (e.g.,
for boron and platinum).
Alexiu et al.163 evaluated modifiers to stabilise Hg in its
determination in pharmaceuticals by ETAAS. Under optimised conditions, the two systems examined (4% H2O2-4%
HCl and 10% PdCl2) gave LODs of 0.1 and 0.02 mg l1,
respectively. The latter was used in the final method, which was
applied to the determination of Hg in thimerosal batches and
in gammaglobulinic vaccines. Satisfactory recovery of added
Hg (96-102%).was demonstrated. The toxic elements, As, Cd
and Hg, were determined by Kim164 in 55 calcium supplements
available on the Korean market. Arsenic and Cd were determined by ETAAS with Zeeman background correction; Hg
was determined with a dedicated Hg analyser. Supplements
made from shark cartilage had the highest Cd and Hg concentrations (mean: 0.13 and 0.06 mg kg1, respectively), but
the daily intake of these elements would still be well within the
338
Provisional Tolerable Daily Intake set by the FAO/WHO Joint
Food Additive and Contaminants Committee.
Traditional plant-based medicines all around the world are
being examined for their trace element content or so it would
seem from the publications in this review year. In Pakistan,
Sahito et al.165 determined 15 elements in different parts of the
plant Azadirachta indica by FAAS. High concentrations of the
essential elements Cu, Fe and Zn were found together with
disturbingly high concentrations of the non-essential element
Al (48-99 mg g1). Herbal medicines in Brazil were analysed
for their Cd, Hg and Pb content.166 Caldas and Machado
digested samples of ten different types of herbal remedies with
HNO3 and determined the elements by AAS. Most levels were
low enough to not be a health concern, but the Pb concentrations found in 3 out of 15 samples of horse chestnut (Aesculus
hippocastanum) were high: 153, 156 and 1480 mg g1, respectively. Consumption of this on a regular basis would provide
up to 440% of the Provisional Tolerable Weekly Intake for Pb.
Also from Brazil, Flores et al.6 applied their direct solid
analysis technique in FAAS to the determination of Cu in
medicinal plants. This technique, described in more detail in
section 1.2.2, allowed more than 50 samples h1 to be measured with an LOD of 1.2 mg g1. Results agreed well with
those obtained after wet digestion and conventional FAAS. In
Serbia, Razic et al.167 determined nine elements in Echinacea
purpurae by FAAS and FAES. The composition in root, stem,
leaves and flowers differed significantly but evaluation of the
data by multivariate methods revealed two distinct groups of
elements showing similar patterns—one containing Cu, Fe, Li
and Mn and a second consisting of Ca, Mg, Ni and Zn. A
method using ETAAS for the determination of Cd in the
Chinese medicine, Dioscorea zingiberensis, was developed by
Chen.168 Palladium was chosen as the chemical modifier.
Arsenic and Hg in seven Chinese medicinal herbs were determined by Long et al.169 with HGAFS and CVAFS, respectively, after microwave-assisted pressure digestion. The LODs
were 0.1 and 0.03 mg l1 for As and Hg, respectively. Results
agreed well with those obtained by ICP-AES. Yang et al.,170
also using HGAFS, were able to speciate AsIII and AsV in a
leachate of Chinese medicines by using prior ion exchange
separation. Simultaneous determination and speciation of As
and Sb in extracts of Chinese medicinal herbs was possible in
the method developed by Sun et al.171 They used HG with a
dual-channel AF spectrometer to measure AsIII, SbIII, total As
and total Sb. In a comparison of different extraction systems,
Soxhlet extraction was the preferred technique.
Much of the published work referring to yeast, garlic and
medicinal plants is concerned with the procedural detail of
speciation, mainly for Se, with some interest in As. Two groups
examined speciation and bioavailability of Se from yeast-based
supplements and intervention agents used in cancer prevention
studies. In the study by Dumont et al.172 yeast supplements
were subjected to in vitro simulated gastrointestinal digestion.
Selenium species in the digests were separated by HPLC for
quantitative determination using ICP-MS and characterisation
using ES-MS-MS. Chromatographic conditions were chosen
to be compatible with both mass spectrometric techniques. The
main Se species extracted by both gastric and intestinal digestion was SeMet. Two minor Se species Se-Cys and Se-(O)methionine were also identified. Larsen et al.173 extracted Se
species from yeast based intervention agents using proteolytic
digestion and quantitatively determined the released species
using ion-exchange HPLC coupled with ICP-MS. Selenomethionine was again the predominant species released in the
digest, together with three other unidentified species. The
authors noted marked differences in the relative amounts of
the Se species in batches of tablets from the same manufacturer
and between tablets from different producers. In more recently
produced tablets, SeMet represented some 54–60% of total Se
compared with only 27% in the tablets used for the national
Table 1
Clinical and biological materials
Element
Matrix
Technique;
atomisation;
presentation
Actinides
Urine
MS;ICP;L
Ag
Skin
XRF;-;-
Al
Brain (rat)
AMS;-;S
Al
Neuroblastoma
cells
MS;ICP;SEC
MS;ICP;CE
Al
Blood, serum,
urine
AMS;-;-
Al
AA;-;L
Al
Amino acids
(human blood)
Serum,
glomerular
filtrate (rat)
Al
Kidney (rat)
SIMS;-;-
As
Tissue (mouse)
PIXE;-;-
As
Chinese herbal
medicines
AF;-;-
As
Urine
MS;ICP;IC
As
Urine (rat)
MS;ICP;LC
As
Hair (human),
clam
AA;ETA;L
As
Chinese herbal
medicines
AF;HG;L
As
Skin (rat)
AA;ETA;-
As
Algae, blood,
packed blood
cells, serum,
urine and
simulated gastric
fluid
Traditional
Chinese
medicines
MS;ICP;
L AF;HG;MS;ICP;
HPLC MS/
MS;ES;HPLC
As
AA;ETA;L
AF;HG;LC
Sample treatment/comments
Ref.
The performance of ICP-MS for the determination of actinides in
urine was investigated and compared with other available techniques
The capability for measuring Ag concentrations in skin was
investigated using an 125I source to excite the Ag K X-rays and a
901 geometry. The lowest detectable concentration was 3–4 ppm
after 10–20 min measurement periods
26
Al from maternal milk reached the brain of suckling rats and
a considerable fraction (12–20%) remained in the brain tissue
throughout their lifetime (ca. 2 y)
The main Al species in neuroblastoma cells exposed to Al lactate
were Al–transferrin complex in control cells and a low Mr
Al-complex in neuroblastoma cells
Al toxicokinetics in patients with chronic renal failure and controls
were investigated using 26Al (given as a single oral or i.v. dose) as
tracer and AMS for the detection of the tracer in blood, urine and
serum fractions
The binding of Al to amino acids present in human blood was
investigated in vitro by combining IC, ultrafiltration and AAS
In an experimental study of renal handling of Al in rats infused
with Al citrate, Al concentrations in serum and glomerular filtrate
indicated greater Al filtration than predicted from an in vitro model
and minimal (19–26%) reabsorption
The high sensitivity of SIMS was exploited to obtain images of the
distribution of Al and In in rat kidney and to confirm the mechanism
of elimination of low doses of Al and In, after their accumulation in
the lysosomes of the proximal tubule cells
In an investigation of As2O3 for the treatment of solid tumours in
a murine xenograft model, As was preferentially accumulated in
tumour rather than other tissues
AsIII was measured in a Chinese herbal medicine (Niuhuang Jiedu
tablets), using 3.6–5.8 mol l1 HCl and 2.0–2.5% NaBH4, followed
by reduction of AsV to AsIII and determination of total As. The
concentration of AsV was calculated by difference. RSD was 0.8–2.9%.
Analytical recovery was 96.7–116.3% and 109.0–116.8% for AsIII
and AsV, respectively
Total As, AsIII, AsV and DMA were determined simultaneously by
isocratic elution using anionic IC coupled with ICP-MS. LODs were
0.31 ng ml1 (AsIII), 0.45 ng ml1 (Asv), and 2.09 ng ml1 (DMA)
DMAIII, MMAIII and TMA, extracted in CCl4 as the
diethylammonium DDC complexes, were determined by LC-ICP-MS
without significant changes in their concentration during storage
or pre-treatment
Ir, Pd and Rh were evaluated as permanent chemical modifiers for
the determination of As in digested biological samples by tungsten
coil ETAAS. The highest sensitivity was obtained with Rh (2.0 mg).
LOD was 29 pg, RSD 4.4% and analytical recovery 94 8%.
Sample throughput was 21 h1
A method was developed for the simultaneous determination of total
As, AsIII, total Sb and SbIII by HG-double channel AFS. Samples (1 g)
were extracted with 9 þ 1 CH3OH–H2O in a Soxhlet extractor and the
aqueous fractions diluted with HCl or acetate buffer for the
determination of the total content or the trivalent species, respectively.
LODs were 9.4 ng g1 (AsIII), 5.6 ng g1 (total As), 6.3 ng g1 (SbIII)
and 1.9 ng g1 (total Sb). Analytical recovery of added As and Sb was
495 and 492%, respectively
Following intradermal injections of NaAs2O3 in rats, increased
vascular permeability was observed. After an initial increase,
tissue As declined rapidly and returned to baseline levels within 1 h
The human metabolism of arsenosugars from the Chinese seaweed
Laminaria was investigated in experimental studies, using NAA,
ICP-MS and HGAFS to determine total As in algae and human
samples, and HPLC-ICP-MS and HPLC- ES-MS/MS to investigate
As species
155
The determination of both AsIII and AsV in traditional Chinese
medicines was achieved using ion exchange chromatography and
HGAFS. LOD was 89 ng ml1 and recovery ranged from 91 to 109%
49
84
86
42
278
85
39
97
206
279
92
94
171
280
281
170
339
Table 1
340
(continued )
Element
Matrix
Technique;
atomisation;
presentation
As
Skeleton fossils
(dinosaur)
AF;HG;AE;ICP;L
As
Chinese medicinal
herbs
AF;HG;L
AF;CV;
L AE;ICP;L
As
Hair
SIMS;-;-
As
Urine
MS;ICP;HPLC
As
Skin
XRF;-;-
As
Urine
AA;HG;HPLC
As
Blood, urine
AA;ETA;L
AA;HG;L
As
MS;ICP;HPLC
As
Environmental
and biological
samples
Urine, wool extract
As
Urine
MS;ICP;HPLC
As
Fingernail, hair,
urine
MS;ICP;HPLC
As
Urine (CRMs,
RMs)
MS;ICP;HPLC
As
Dietary calcium
supplements
AA;ETA;L
AA;CV;L
Au
Serum (dog)
AA;-;L
B
Soft tissue
SIMS;-;AE;ICP;-
B
Serum, urine
AA;ETA;L
B
Blood plasma,
urine
MS;ICP;L
MS;ICP;HPLC
MS;ES;HPLC
MS;ES;L
Ref.
Samples of skeleton fossils of dinosaurs unearthed in China were
digested with aqua regia at 100 1C, prior to As determination by
HGAFS and ICP-AES (for comparison). LOD was 0.03 mg l1
and recovery ranged from 97 to 109%. Higher As concentrations
were found in the skeleton fossils suggesting that As toxicosis
contributed to their extinction
As was determined by HGAFS and Hg by CVAFS in Chinese
medicinal herbs after closed-vessel microwave digestion. Analytical
conditions were optimised using an orthogonal design. ICP-AES
was used for comparison (As). LODs were 0.1 ng ml1 (As) and
0.03 ng ml1 (Hg)
Using nano-SIMS 50, ion imaging was performed on microtomed
hair cross-sections to determine As concentration and distribution.
The linearity of the relationship between the SIMS signal and
As concentration was demonstrated
As species were determined in urine by HPLC-ICP-MS with a hexapole
collision cell and an ion-exchange column. The mobile phase was
0.1 mmol l1 EDTA–10 mmol l1 NH4NO3–0.05% HNO3. AsV,
MMA, DMA, AsIII and AB were separated within 14 min, but
AC, TMAO and TMI eluted together at about 40 min
The preliminary results of the development of an XRF system to
measure skin As in vivo were reported. LODs were 3.5 0.2 and
10.3 0.5 ppm in 90 and 1801 measurement geometries, respectively,
for a measurement time of 30 min
A method for the simultaneous quantification of AsIII, AsV, MMA,
DMA and TMAO in human urine by HPLC-HGAAS via a
FI interface was presented. LODs ranged from 1.1 (TMAO) to
2.6 mg l1 (AsV)
Methods for blood and urine mineralisation in the presence of different
As species, prior to the determination of As by HGAAS or ETAAS,
were investigated
A review of As toxicity and currently used sample treatment and
detection procedures for As quantification and speciation was
presented
Dimethylarsinothioic acid was identified (by HPLC, coupled
simultaneously to ICP-MS and ES-MS, quadrupole TOF-ES-MS and
1
H NMR) as the main product of the in vitro reduction of methylated
AsV species with Na2S2O5/Na2S2O3 and was also found in urine
and wool extract from sheep feeding on seaweed
AB and DMAV were the major As species excreted (together with
other unknown metabolites) in urine from 9 volunteers who ate a
meal of blue mussels. Individual difference in the excretion patterns
were observed
As species in samples (urine, H2O–CH3OH extract of freeze-dried
red blood cells, TCA treated plasma, and water extract of hair and
fingernails) from Bangladesh people and controls were investigated
as biomarkers of As exposure
As species were determined in two CRMs (NIES 18 and NIST
SRM2670a) and three other RMs, diluted 1 þ 3 prior to analysis by
gradient elution anion or cation exchange HPLC-ICP-MS. Of several
As species, 9 were identified. As species concentrations added up to the
target values for total As
Mean concentrations of As, Cd and Hg in calcium supplements, as
determined by Zeeman-effect ETAAS after microwave-aided digestion
(As, Cd) and by an Hg analyser, were 0.48, 0.02 and 0.01 mg kg1,
respectively
The preclinical tolerance and pharmacokinetics of a novel
chemotherapeutic agent, tetrakis(trishydroxymethyl)phosphine
AuI Cl, were assessed in dogs
Dynamic SIMS was used to obtain images showing the distribution
of 10B in biological tissues, as part of research into B NCT.
Results obtained on tissue standards, as B : C signal ratios,
correlated to B measurements by ICP-AES
B concentrations were significantly lower in serum and urine of
menopausal women compared with controls
B was determined in blood plasma and urine by ICP-MS, using ID
and a high efficiency DIN. Protein precipitation with HNO3 removed
98
169
95
91
50
282
93
87
89
90
75
283
164
109
41
100
99
Table 1
Element
(continued )
Matrix
Technique;
atomisation;
presentation
Ref.
1
Bi
Urine
AA;ETA;FI
Ca
Serum
MS;ICP;L
Ca
Diet, faeces, urine
and sweat
AA;-;-
Cd
Cd
Urine
Natural waters,
urine
AA;ETA;FI
AA;ETA;FI
Cd
Chinese herbal
medicine
AA;ETA;-
Cd
Urine
AA;ETA;L
Cd
Blood
AA;ETA;L
Cd
Biological and
environmental
samples
AA;-;L
Cd
Medicinal herbs
AA;-;-
Cd
Biological and
environmental
samples
AA;ETA;-
Cd
Urine
AA;ETA;L
Cd
Hair, nail
AA;F;AA;ETA;-
Cd
Biological CRMs
AA;ETA;L
Cd
Dietary calcium
supplements
Serum
AA;ETA;L
AA;CV;L
AA;ETA;L
Co
94% of C. LOD was 0.6 ng ml and RSD o2.0% for blood plasma
and o1.3% for urine samples
On-line preconcentration with a laboratory-made FI system coupled to
multi-element ETAAS was applied to the simultaneous detection of Bi,
Cd and Pb in urine. LODs were 0.013 (Bi), 0.002 (Cd), and 0.0045 (Pb)
mg l1. Analysis of RMs yielded results within 90–110% of the
target values
Proteins in serum samples (20 ml) were precipitated with diluted HNO3
and the 42Ca : 43Ca ratio in the supernatant measured by magnetic
sector ICP-MS with a precision o0.5%. Results compared well
with oxalate precipitation, requiring at least 0.5 ml serum
Mineral (Ca, Mg, P) balance studies were carried out on Japanese
volunteers over a 14 y period. The Ca, Mg and P content of diet, faeces,
urine and sweat were measured by AAS (Ca, Mg) and UV
spectrophotometry (P)
See Bi, ref. 11
A new phase separator improved the separation of organic
extracts from large volumes of aqueous phase. With NH4
diethyldithiophosphate in IBMK, the enrichment factor for Cd
was 24.6, LOD 2.8 ng l1 and RSD at 0.2 mg l1 Cd 3.2%
Pd was chosen as the chemical modifier for the determination of Cd in
Dioscorea zingiberensis, a Chinese herbal medicine. LOD was 0.075 ng
ml1 and RSD 3.8%. Analytical recoveries were between 90–110%
Cd and Pb were determined by means of simultaneous ETAAS with
end-capped THGA in urine samples diluted 1 þ 4 with 0.125% (m/v)
Triton X-100–2.5% (v/v) HNO3–0.31% (m/v) NH4H2PO4. LODs were
0.03 mg l1 (0.36 pg) for Cd and 0.57 mg l1 (6.8 pg) for Pb. Increased
sensitivity (14% and 25% for Cd and Pb, respectively) was observed
in comparison with standard tubes
Blood samples were diluted 1 þ 9 with 0.11% (m/v) Triton X-100 –
1.1% (v/v) HNO3 prior to Cd and Pb simultaneous determination
by Zeeman-effect ETAAS. W (250 mg)–Rh (200 mg) was used as
permanent chemical modifier. Charring and atomisation temperatures
were 400 1C and 1500 1C, respectively, and total analysis time was
63 s. LODs were 0.03 mg l1 (Cd) and 0.8 mg l1 (Pb) and analytical
recovery 101% (Cd) and 98–100% (Pb)
Cd21, Cu21 and Pb21 in environmental and biological samples were
separated and preconcentrated by solid phase extraction on C18
membrane disks modified with bis-2-thiophenal propandiamine,
prior to analysis by AAS. LODs were 0.01 (Cd), 0.02 (Cu) and
0.25 (Pb) ng ml1
The content of Cd, Hg and Pb in herbal medicines used in Brazil was
determined by AAS after HNO3 digestion. LODs were 0.20, 0.01 and
2.0 mg kg1, for Cd, Hg and Pb, respectively. Only Pb intake from
horse chestnut taken on a long-term basis may be of health concern
The efficiency of HNO3, Ni, Pd and Th as chemical modifiers for the
determination of Cd by ETAAS, using platform and fast temperature
programs, was compared. Ni (with HNO3) gave the highest sensitivity.
LOD was 0.03 ng ml1 and m0 0.35 pg
Cd was determined in 10 ml urine after 1 þ 1 dilution with 4.0% HNO3.
Analytical conditions were optimised using a fractional factorial
design. LOD was 0.12 mg l1 and m0 1.78 pg
Hair and nail Cd concentrations were significantly correlated in
both exposed and non-exposed subjects, but only nail levels were
significantly higher in exposed subjects. Hair and nail Pb levels were
significantly correlated only in exposed subjects, but both were
higher than in controls
A novel digestion procedure for organic materials was reported.
Samples (50–250 mg) were wrapped in paper and placed in a
microwave oven for 20 s at 1400 W after addition of NH4NO3 and O2.
After combustion and a reflux step with concentrated HNO3
the residual C concentration was o0.4%
See As, ref. 164
Serum Co levels after metal-on-metal total hip arthroplasty were only
slightly increased compared to controls and remained stable over
a 5 y period
11
102
284
11
13
168
63
62
7
166
285
101
77
3
164
104
341
Table 1
342
(continued )
Technique;
atomisation;
presentation
Element
Matrix
Co
Vitamin B12 tablets
AA;F;L
AA;ETA;L
Co
Oral mucosa cells
MS;ICP;-
Co
Skin, sweat
(synthetic)
AA;ETA;L
Co
Hair
AA;F;L
Cr
Saline solutions
AE;ICP;L
Cr
Natural waters,
urine
AA;ETA;L
Cu
Serum, nails
AA;-;-
Cu
Liver tissue
MS;ICP;LA
Cu
Serum
AA;-;L
Cu
Serum
AE;ICP;L
Cu
Plasma, human
milk
AA;-;L
Cu
Liver
PIXE;-;-
Cu
Serum
AA;-;L
Cu
AA;-;L
Cu
Biological and
environmental
samples
Nails, serum
AA;-;-
Cu
Brain (rat)
AA;-;L
Cu
Erythrocytes
AA;-;-
Cu
Erythrocytes,
serum
XRF;-;-
Cu
Serum
(dromedary)
AA;F;L
Ref.
The preconcentration of Co complexes with pyridylazo compounds
(PAN, PAR, 5-Br-PADAP) was achieved using Triton X-100 and SDS,
as a novel mixed micellar system, and inducing phase separation by
HCl or NaCl addition. LOD was 1.6 mg l1, linear range 25–200 mg l1
and extraction recovery 98–102%. The results were compared
with ETAAS
Co and Ni levels in oral mucosa cells were about 3-fold higher in
orthodontic patients than controls and significantly and positively
correlated with the results of cell viability and comet assays
Measurements of Co by ETAAS and Co21 by differential-pulse
polarography in human skin, donor and/or receiving phases, as parts
of an in vitro system, demonstrated for the first time how Co
can permeate through the skin
A solid phase extraction and 200-fold preconcentration procedure for
the determination of Co and Ni in hair was developed. Their ethyl
xanthate complexes, quantitatively retained on benzophenone in the
pH range of 8.0–10.0, were dissolved in 5 ml of DMF and analysed
by FAAS
The release of metals from stainless steel and Ni–Ti orthodontic alloys,
kept in a 0.9% NaCl solution for 1 month, was measured by ICP-AES.
No effect was observed on the survival and DNA synthesis of
human fibroblasts exposed to the immersion media
The preconcentration and separation of Cr species in natural waters
and urine was obtained by an automated combination of chelation or
anion exchange chromatography and ETAAS. LODs for CrIII
and CrVI were 0.14 and 0.08 ng ml1, respectively
In patients with migraine, serum Cu and Mn levels were higher and Zn
lower than in controls, but, in nails, only Mn levels were
significantly higher in patients
The precision of a method for two-dimensional mapping of Cu and Zn
in liver sections, based on LA-ICP-TOF-MS, was assessed on a pig
liver CRM, using C as an internal standard, and ranged from
1.6 to 6.1%
Patients with dilated cardiomyopathies had higher Cu and lower
Zn concentrations in serum than controls. Mg levels did not
differ significantly
A method for the simultaneous determination of Cu and Fe in serum
by UV detection of their complexes with 2-(5-bromo-2-pyridylazo)-5(N-propyl-N- sulfopropylamino)aniline was compared with ICP-AES.
LODs were 0.4 mg l1 (Cu) and 0.2 g l1 (Fe) and RSD was o1%
In a study of 191 mothers, Cu, Fe and Zn levels in milk were not
dependent on maternal trace element status, as assessed from plasma
Cu and Zn concentrations and indices of Fe status (haemoglobin,
plasma ferritin, soluble transferrin receptors and zinc protoporphyrin)
The liver content of Cu, Fe and Zn in patients with chronic liver disease
caused by hepatitis C virus was measured in thin-needle biopsy
specimens. Cu levels were higher in patients with hepatocellular
carcinoma
Maternal and cord blood serum levels of Cu, Fe and Zn in a sample of
Jordanian women and their newborns were reported
See Cd, ref. 7
10
Cu, Mn and Zn concentrations were determined in nails and serum
from patients with epilepsy and controls. Cu in serum and Mn in
nails were significantly higher in patients than controls
Cu, Fe and Zn levels in rat cerebral cortex were measured after wet
ashing to investigate alterations of physiological conditions due
to subacute or subchronic exposure to formaldehyde
In patients, who had undergone high-dose chemotherapy and
autologous stem cell transplantation, erythrocyte Fe and Zn,
but not Cu, levels, increased together with oxidative stress markers
In patients with hyperthyroidism, serum, but not erythrocyte, Cu
and Zn levels changed significantly after therapy with 131I and were
positively correlated with triiodothyronine and thyroxine
Cu supplementation had no effect in dromedaries with normal Cu
serum levels, but serum Cu increased to normal values in Cu
deficient animals
105
103
9
132
12
286
37
107
287
108
54
65
7
288
289
290
60
291
Table 1
(continued )
Element
Matrix
Technique;
atomisation;
presentation
Cu
Cu
Plasma
Human arteries
AA;-;L
MS;ICP;-
Cu
MS;ICP;SEC
Cu
Metallothionein
fractions (rat liver
and kidney)
Serum, ultrafiltrate
AA;ETA;L
Cu
Medicinal plants
AA;F;S
Cu
Cu
Biological CRMs
Human milk and
infant formulas
AA;ETA;L
AA;ETA;L
Cu
Plasma
AA;-;
L MS;ICP;L
Cu
Serum
AA;F;
L AA;ETA;L
Fe
Cancer tissue
XRF;-;-
Fe
Fe
Fe
Fe
Fe
Serum
Brain (substantia
nigra)
Plasma, human milk
Liver
Serum, transferrin
AE;ICP;L
XRF;-;XANES;-;AA;-;L
PIXE;-;MS;ICP;
HPLC
Fe
Fe
Fe
Fe
Serum
Brain (rat)
Erythrocytes
Food, human faeces
AA;-;L
AA;-;L
AA;-;MS;ICP;-
Fe
Fe
Erythrocytes, serum
Erythrocytes
XRF;-;MS;ICP;L
Fe
Human arteries
Gd
Human
glioblastoma
cells
Hair
MS;ICP;EPR;-;SIMS;-;-
Hg
AF;CV;GC
Hg
Brain, kidneys, liver
(mouse)
AA;CV;-
Hg
Hg
Medicinal herbs
Scalp hair, urine
AA;-;AA;-;-
Ref.
Zn supplementation in infants did not influence Cu status
The quantification of Cu and Fe by EPR spectroscopy and
ICP-MS provided evidence for increased levels of Cu and Fe in
carotid lesions in comparison with healthy human arteries
The binding of metals (Cu and Hg) in tissues of rats fed cinnabar
and controls was investigated
292
30
Solid phase extraction and ultrafiltration were compared for the
separation of free and protein-bound serum Cu
0.05–1.5 mg of ground sample (o80 mm) were introduced directly into
the flame as a dry aerosol using a T-quartz cell set between the burner
and the optical path. Characteristic mass was 0.8 ng Cu and absolute
LOD 1.2 ng. The results were compared with those obtained after
sample digestion
See Cd, ref. 3
The influence of gastric pH in the first stage of enzymolysis on
the bioavailability of Cu from human milk and infant formulas
was evaluated in vitro
A method was reported for the selective extraction of exchangeable
Cu from blood plasma, based on dialysis in the presence of histidine
and subsequent Cu pre-concentration with Chelex-100
Albanian immigrant mothers and their neonates (n ¼ 820) had
significantly lower serum Cu and Se levels than Greek mothers
and their children (n ¼ 1118), as a consequence of lower animal
protein, Cu and Se intakes
In a prospective randomised trial, Fe concentrations in intestinal
cancer tissue and in colon and rectum polyps were investigated by
TRXRF
See Cu, ref. 287
XRF and XANES were applied to investigate the distribution
and chemical state of Fe in brain tissue
See Cu, ref. 108
See Cu, ref. 54
In a study of the binding patterns of V to serum transferrin by
anion-exchange HPLC-HR-ICP-MS, 56Fe, 32S and 51V could be
monitored simultaneously at a resolution of 4000 in samples of
1 ml serum or 2 mg transferrin
See Cu, ref. 65
See Cu, ref. 289
See Cu, ref. 290
Fe isotope ratios were determined in food and human faeces by double
focusing ICP-MS, using a resolution of 3000 to overcome interferences
(40Ar16O, 40Ar14N)
See Cu, ref. 60
Isotope ratios (56Fe : 54Fe and 57Fe : 54Fe) were measured in
erythrocytes by MC-ICP-MS. Interferences were reduced using a
desolvating nebuliser and separation of Fe from the matrix by IC
See Cu, ref. 30
106
In support of NCT, SIMS was applied to map the subcellular
distribution of 157Gd and the other 6 naturally occurring Gd isotopes,
in human glioblastoma cells
Methylmercury was determined in hair by GC-CV-AFS, after
headspace solid phase microextraction. Both the GC-CV-AFS
interface set-up and the digestion parameters (acid type, concentration,
temperature and time) were optimised, to avoid methylmercury
degradation. The stability of the digested samples was evaluated
The determination of Hg content in tissues of albino and pigmented
mice treated with Hg-containing skin-lightening creams showed
that Hg was readily absorbed through the skin, but melanin had a
protective role
See Cd, ref. 166
A standardised procedure evaluating Hg burden was developed based
on measurements of Hg in scalp hair and urine samples from 2223
subjects (before and after administration of DMPS) and Hg release
from dental amalgams by a newly developed, amalgam specific
chew test
293
6
3
294
295
296
113
287
45
108
54
297
65
289
290
111
60
110
30
40
128
298
166
126
343
Table 1
Element
Matrix
Hg
Metallothionein
fractions (rat liver
and kidney)
Chinese medicinal
herbs
Hg
Technique;
atomisation;
presentation
Ref.
MS;ICP;SEC
See Cu, ref. 293
293
See As, ref. 169
169
The use of PdCl2 (10%) as the chemical modifier gave a better LOD
(0.02 mg ml1) than 4% HCl–4% H2O2 (0.1 mg ml1). Ashing and
atomisation steps were carried out at 250 1C and 1800 1C, respectively.
Recovery was 96–102%
Hg was measured, by CVAAS and CVAFS, respectively, in blood and
hair samples from pregnant women and their newborns. Hg levels in
cord blood were significantly higher than in maternal blood and
influenced by fish consumption before and during pregnancy
An on-line pre-concentration procedure, based on solid phase
extraction with automatic sequential dispensing, was devised. With the
aid of a laboratory-made device, connected directly to the ICP-AES
torch, the APDC–Hg complex was retained on PTFE turnings, SnCl2
added, and Hg purged into the plasma using an Ar flow. The method
was linear over the range 0.02–5.0 mg l1, LOD was 0.01 mg l1
and RSD 3.1% at 1.0 mg l1. Under the stated conditions, sample
throughput was 30 h 1
Hg was determined by FI-CVAAS in 300 ml blood, diluted 1 þ 1 v/v
with 10% v/v TMAH, incubated for 1 h at room temperature and
further diluted 1 þ 4 v/v with 2% v/v HCl. LOD was 0.2 mg l1 and bias
2.5%. Precision (o10%) was better than with on-line microwaveassisted digestion
The evidence of exposure to Hg and Pb and the mechanisms of
acquisition and storage of these metals at early stages of human
development were reviewed
The release of Hg0 from in situ fillings and in vitro amalgam specimens
was investigated using Zeeman-effect ETAAS coupled with an
electronic controlled apparatus allowing aspiration of (oral) air under a
standard protocol. RSD for repeated sampling from a single patient
ranged from 18 to 25%. The increase in Hg0 levels after insertion of
new fillings was detectable even in the presence of old ones
See As, ref. 164
163
Hg
Pharmaceuticals
AF;HG;L
AF;CV;L
AE;ICP;L
AA;ETA;-
Hg
Blood (maternal and
cord), hair
AA;CV;L
AF;CV;-
Hg
Seafood (CRM),
blood, hair and urine
AE;ICP;CV
Hg
Blood
AA;CV;FI
Hg
Human and cow
milk
-;-;-
Hg
Oral air
AA;ETA;L
Hg
Dietary calcium
supplements
Kidney (rat)
Erythrocytes, blood
plasma
AA;ETA;L
AA;CV;L
SIMS;-;AA;-;-
Mg
Mg
Serum
Serum, hair and
lenses
AA;-;L
AA;-;-
Mg
Faeces, erythrocytes,
urine
TIMS;-;MS;ICP;L
Mg
Diet, faeces, urine
and sweat
Serum, nails
Blood, brain, lung,
liver (rat)
Nails, serum
Human milk
AA;-;-
In
Li
Mn
Mn
Mn
Mn
344
(continued )
AA;-;AA;-;AA;-;AE;ICP;L
MS;ICP;HPLC
Mn
Vitamin-mineral
tablets
AA;ETA;S
Mo
Blood plasma
MS;ICP;L
Ni
Oral mucosa cells
MS;ICP;-
79
21
88
117
125
164
See Al, ref. 39
In a retrospective study of 165 patients treated with Li salts, the
concentrations of Li1 in erythrocytes and plasma and their ratio
were evaluated as indices of toxicity
See Cu, ref. 107
Mg and Zn were measured in serum, hair, and lens from diabetic and
nondiabetic patients, who underwent surgery for senile cataracts. Only
lens Zn levels were significantly higher in diabetic than in nondiabetic
patients
Mg absorption was determined from the concentration of the tracer
25
Mg in 24 h urine pools or erythrocytes collected 14 days after
challenge as an alternative to faecal collections
See Ca, ref. 284
39
121
See Cu, ref. 286
Mn content was increased in tissue but not in blood of rats exposed
to stainless steel welding fumes
See Cu, ref. 288
Mn species in subfractions of human milk obtained by centrifugation
were investigated by ICP-AES and SEC-ICP-MS. The defatted
fraction contained approx. 2.9 mg l1 Mn, most of which was in the low
Mr fraction. Both Mn21 and Mn citrate complex were identified in the
respective SEC fractions by strong anion exchange ICP-MS
Finely-ground samples were introduced directly into the furnace by
means of a solid autosampler system. Calibration with aqueous
standards, standard additions or solid certified standards was
investigated. The results were compared with those obtained after acid
digestion
Plasma Mo levels, determined by ID-ICP-MS in an experimental
human study, reflected dietary Mo intake
See Co, ref. 105
286
124
107
299
122
284
288
123
214
130
105
Table 1
(continued )
Element
Matrix
Technique;
atomisation;
presentation
Ni
Ni
Ni
Saline solutions
Hair
Tissue extracts
AE;ICP;L
AA;F;L
MS;ICP;HPLC
P
Biological samples
MS;ICP;L
P
AA;-;-
Pb
Diet, faeces, urine
and sweat
Blood
AA;-;-
Pb
Pb
Urine
Tooth enamel
AA;ETA;FI
MS;ICP;LA
Pb
Pb
Pb
Urine
Blood
Blood
AA;ETA;L
AA;ETA;L
AA;ETA;L
Pb
AA;-;L
Pb
Biological and
environmental
samples
Blood, milk (cow)
AA;-;L
Pb
Pb
Medicinal herbs
Teeth
AA;-;AA;ETA;-
Pb
Hair
AA;F;HG
Pb
Hair, nail
Pb
Blood
AA;F;AA;ETA;AA;ETA;L
Pb
Blood, bone, human
milk
Pb
Bone
AA;ETA;L
XRF;-;MS;ICP;L
XRF;-;-
Pb
Blood
AA;ETA;L
Pb
Dialysis concentrates
AA;HG;FI
AA;ETA;L
Pb
Human and cow
milk
Bone, blood
-;-;-
Pb
XRF;-;AA;ETA;L
Ref.
See Cr, ref. 132
See Co, ref. 9
Seven Ni species were separated from tissue extracts by a novel
procedure based on the coupling of sequentially applied
anion-exchange and SEC with SF ICP-MS
P and S were detected as PO1 and SO1 by DRC-ICP-MS, using O2 as
the reaction gas. The method was applied to the detection of
phosphoproteins in HCl digests. The P : S ratio allowed differentiation
of malignant cell lines from primary cultures and cancerous from
normal tissue in needle biopsies (0.2–0.5 mg) from 4 patients.
Phosphoproteins were detected from polyacrylamide gels using
LA-ICP-MS with a LOD of 0.6 mg g1, but S detection was
hampered by the high S content of blank gels
See Ca, ref. 284
132
9
131
In a paediatric population blood Pb levels were significantly reduced
over the period 1991–2001. Blood zinc protoporphyrin increased
sharply only at blood Pb concentrations above 18 mg dl1
See Bi, ref. 11
LA was compared with sample digestion for the determination of the
Pb : Ca ratio in the enamel of deciduous incisors (a biomarker of
in utero Pb exposure) by ICP-MS. LOD for Pb was 11 mg kg1 and
the RSD for the Pb : Ca ratio was 3.4%
See Cd, ref. 63
See Cd, ref. 62
Pb was determined in blood by ETAAS using Pt as chemical modifier.
Tantalum foil lining extended the tube life. LOD was 1.74 mg l1,
RSD o5% and analytical recovery 96%–103%
See Cd, ref. 7
119
The circadian variations of Pb in blood and milk of dairy cows after
intravenous administration of CH3COOPb in winter were investigated
See Cd, ref. 166
Pb was determined by ETAAS in the superficial enamel of deciduous
teeth from pre-school children (Brazil). The sampling technique
involved application of 5 ml of 1.6 mol l1HCl in 70% (v/v) glycerol
to a delimited tooth area (1.6 mm diameter). Biopsies deeper than
3.9 mm gave more reliable results
Nebulisation assisted by HG with K3Fe(CN)6–HCl improved the
sensitivity (13.4 fold) of Pb determination in hair. LOD was 2.8 mg l1
and the analytical recovery range 96–99%
See Cd, ref. 77
Pb concentration was significantly higher in earlobe than in
corresponding venous blood samples from 126 occupationally
exposed subjects
The relationships between Pb in blood and bone (as indices of previous
or current exposure) and Pb in human milk were investigated
in a sample of lactating Mexican women
Because body Fe burden is inversely associated with Pb absorption,
the association of the C282Y and/or H63D haemochromatosis gene
with body Pb burden was investigated among elderly men in the
Normative Aging Study
The estimate of uncertainty from performance data was demonstrated
using the determination of Pb in blood by Zeeman-effect ETAAS
as an example and comparing different approaches to the estimate
of trueness
Pb levels ranging from 10 to 70 ng ml1 were determined in dialysis
concentrates by FI-HG-AAS. LOD was 0.7 ng ml1 for a 500 ml
injection volume. RSD was 3.7% at 20 ng ml1. Results were
compared with those obtained on the same samples by ETAAS after
removal of the matrix by solid phase extraction with Chelex 100
See Hg, ref. 117
In a study of bone and blood Pb levels in minorities living in the Boston
(USA) area, statistical analysis of data suggested higher bone Pb levels
in subjects 455 y, even when compared to white subjects of
similar profiles
133
284
11
38
63
62
300
7
232
166
120
78
77
115
118
116
114
301
117
302
345
Table 1
Element
Matrix
Technique;
atomisation;
presentation
Pb
Blood
AA;ETA;L
Pb
Blood, bone
XRF;-;AA;ETA;L
Pd
Animal tissue
(mussels)
AA;ETA;L
XRF;-;-
Pd
Polymers,
pharmaceuticals,
auto catalyst RM
AA;ETA;S
Pd
AE;ICP;ETV
Pd
Biological and
environmental
samples
Urine
MS;ICP;L
Pt
Water, urine
MS;ICP;HPLC
Pt
Liver (rat)
AA;-;-
Pt
Pt
Animal tissue
(mussels)
Breast cancer cells
AA;ETA;L
XRF;-;MS;ICP;-
Pt
Reaction buffer
AA;-;-
Pt
Biological and
environmental
samples
Urine, airborne
particulate matter
AE;ICP;ETV
Pt
Pt
Urine
Plasma, ultrafiltrate,
and urine
MS;ICP;L
MS;ICP;L
Pt
Urine
MS;ICP;L
Pt
Ultrafiltrates
AA;-;L
Pu
Urine
MS;ICP;L
Rh
Animal tissue
(mussels)
AA;ETA;L
XRF;-;-
Pt
346
(continued )
MS;ICP;L
Ref.
In a longitudinal study (Instanbul) of infants up to 2 y old, blood Pb
levels increased with age. Consumption of herbal tea and living with
smokers in centrally heated homes were identified as risk factors for
higher blood Pb levels as well as fathers’ occupations as manual
workers
In a prospective study, changes in renal function in relation to baseline
Pb levels in blood, patella and tibia (mean values: 6.5 mg dl1, 32.4 mg
g1, and 21.5 mg g1, respectively), diabetes, and hypertension were
assessed among middle-age and elderly men. Results suggested that
decline of renal function depended on both bone and blood Pb levels,
with a more pronounced effect in diabetic and hypertensive subjects
A method for the routine determination of Pd, Pt and Rh in animal
tissues, based on microwave-aided digestion and ETAAS was
evaluated and compared with adsorptive CSV (Pt and Rh) and TXRF
(Pd). LODs were 90 ng g1 (Pd), 270 ng g1 (Pt) and 13 ng g1 (Rh),
RSDs o10% and analytical recoveries 495%
A novel approach, based on solid sampling, was proposed for the direct
determination of Pd in various matrices. The procedure allowed
calibration with aqueous standards and reduced risk of analyte losses
and contamination. LOD was 0.4 ng g1 and RSD ranged from
3 to 15%
A novel method was described for the determination of Pd, Pt and Rh,
based on the introduction of their DDC complexes into the plasma by
ETV at 1100 1C. LODs were 1.4 (Pd), 5.4 (Pt) and 0.8 (Rh) ng ml1
The concentrations of Pd, Pt and Rh in urine samples from residents in
either a rural or an urban area were determined by SF-ICP-MS after
1 : 4 (v/v) dilution of the samples
HPLC-ICP-MS, with on-line ID, was applied to the speciation of
cisplatin and its degradation products in aqueous solutions of Cl and
in human urine. LODs were 0.74, 0.69 and 0.65 mg l1 for cisplatin,
monoaqua- and diaquacisplatin, respectively
The delivery rate and tissue distribution of carboplatin, an anticancer
agent, released from implants into rat livers after radiofrequency
ablation, were investigated
See Pd, ref. 139
303
A systematic study of intracellular Pt uptake and accumulation ratio in
breast cancer MCF-7 cell line was performed, using sub-acute
concentrations of various PtII complexes. ICP-MS was chosen for
Pt quantification at low concentrations
The binding of Pt drugs (oxaliplatin, carboplatin, and cisplatin) to
glutathione was monitored by UV-absorption spectroscopy,
HPLC and AAS
See Pd, ref. 138
Pt was determined in urine samples from 100 adults from Budapest and
Vienna by ICP-MS after 10-fold dilution with bidistilled water.
Airborne particulate matter samples, collected in the same cities,
were also analysed
See Pd, ref. 135
The determination of Pt in plasma, ultrafiltrate and urine of patients
treated with antitumour agents was reported. LOQs were 1.0, 0.1,
and 2.0 mg l1 in the 3 matrices
Pt levels in urine, measured by SF-ICP-MS, did not differ between
policemen involved in controlling traffic and those working only in
offices
In a study of the pharmacokinetics of carboplatin administered in
combination with the bradykinin agonist, ultrafilterable Pt was
measured
A rapid method for the assessment of high exposure to 239Pu in
emergencies was developed. 239Pu was determined in 1 ml urine by
magnetic sector ICP-MS with a desolvating introduction system, after
solid phase extraction. LOD was 0.16 fg ml1 and RSD ranged from
2.2 to 3.7%. Results obtained on RMs were within 2.6% of target
values (1–100 fg ml1)
See Pd, ref. 139
304
139
5
138
135
140
305
139
142
143
138
134
135
137
136
141
158
139
Table 1
(continued )
Element
Matrix
Rh
Biological and
environmental
samples
Urine
Serum, transferrin
Biological samples
Chinese herbal
medicines
Plasma
Rh
S
S
Sb
Se
Technique;
atomisation;
presentation
Ref.
AE;ICP;ETV
See Pd, ref. 138
138
MS;ICP;L
MS;ICP;HPLC
MS;ICP;L
AF;HG;-
See
See
See
See
135
297
133
171
AA;ETA;L
Calibration with the standard additions method or matrix matched
standards gave significantly different results. No significant change of
plasma Se content was observed after storage at 20 1C for 1 y
Selenoproteins in red blood cells extracts and yeast were separated
by gel electrophoresis and detected by LA-DRC-ICP-MS. Among
reaction gases (CH4, CO, NH3, O2 and Ar–H2) CO offered the best
performance. LOD was 0.07 mg Se g1 gel with single hole drilling
and 0.15 mg Se g1 gel for ablation with translation
Blood and serum samples were diluted with 10 g l1 Pd in 15% HNO3
and centrifuged prior to Se determination by Zeeman-effect ETAAS.
LOD was 0.4 mmol l1. RSD was 4.5% (blood) and o1.7% (serum).
Analytical recovery was 102.3% (blood) and performance in an
External Quality Assessment Scheme for serum Se was within 1 SD
of the target values
The application of analytical techniques, such as NAA, ICP-MS,
XRF and PIXE, to the investigation of Se metabolism and Se-proteins
in mammals was reviewed
Se species in urine were investigated by reversed-phase and ion-pair
HPLC-ICP-MS and by CE-ES-MS. Urine was pre-concentrated by
evaporation under N2 at room temperature (10-fold) or lyophilisation
(100-fold) and extracted with CH3OH. Nebuliser performances
(modified direct injection versus microconcentric combined with a
cyclonic spray chamber) were compared. At least 10 Se compounds
were separated. Se-methylselenogalactosamine was reported as the
main species in urine of volunteers not supplemented with Se
145
A method was developed for the determination of Se in erythrocytes,
after microwave-aided digestion. Measurements were carried
out at mass 82
Total Se and SeMet were determined by ICP-MS (coupled with HPLC
for the analysis of Se amino acids) in serum and prostate tissue from
prostate cancer patients. Both were within expected normal ranges
Serum Se levels decreased significantly after physical exercise only
in subjects undertaking high physical activity
Median Se levels in autopsy liver tissue samples from Greenlandic Inuit
were higher than in samples from Danes (p o 0.0001), the difference
attributed to higher intake of fish and sea mammals in the former
By means of successive HPLC-ICP-MS and HPLC-ES-MS-MS, SeMet
was identified as the main Se species extracted from yeast supplements,
during simulated digestion processes, in in vitro gastric and intestinal
digests
Three methods of sample preparation (dilution, microwave digestion
and ethanol addition), choice of internal standard (Sc, Rh, In) and
spectral resolution were evaluated for the determination of Se in
human plasma using magnetic sector ICP-MS. Ethanol addition
(0.5% v/v) to a 1 þ 9 dilution of the sample gave the best results.
ETAAS was used for comparison
Se levels in toenail, determined by DRC-ICP-MS after microwaveaided closed vessel digestion, did not differ significantly between
patients with prostate cancer and controls
In multiple regression analysis, neonate serum Se concentration was
significantly associated only with gestational age (P ¼ 0.012). Mother–
child serum Se difference declined with gestational age and birth weight
Samples of human milk (1 g) were digested with a mixture of H2SO4–
HNO3–H2O2 prior to analysis by HGAFS. The digestion of 20 samples
was completed in 3 h. LOD was 2.5 ng g1 and the relative expanded
uncertainty (95%) was 10%
308
Se
Red blood cell
extracts, yeast
MS;ICP;LA
Se
Blood, serum
AA;ETA;L
Se
Biological samples
MS;ICP;- XRF;;- PIXE;-;-
Se
Urine
MS;ICP;HPLC
MS;ES;CE
149,150
Se
Erythrocytes
MS;ICP;L
Se
Serum and prostate
tissue
MS;ICP;HPLC
Se
Serum
AA;-;L
Se
Liver
XRF;-;-
Se
In vitro gastric and
intestinal digests
MS;ICP;L MS/
MS;ES;HPLC
Se
Blood plasma
MS;ICP;L
AA;ETA;L
Se
Toenails
MS;ICP;-
Se
Serum (cord and
maternal blood)
AA;-;L
Se
Human milk
AF;HG;L
Pd, ref. 135
Fe, ref. 297
P, ref. 133
As, ref. 171
35
306
307
309
310
53
172
144
83
311
146
347
Table 1
Technique;
atomisation;
presentation
Element
Matrix
Se
Blood plasma and
erythrocytes
AA;ETA;-
Se
Serum (RMs)
AA;ETA;L
MS;ICP;L
Se
In vitro systems, liver
cytosol (rat)
MS;ICP;HPLC
MS;ES;-
Se
Serum
Sr
Urine
AA;F;L
AA;ETA;L
MS;ICP;L
Th
Urine
MS;ICP;L
Ti
Bone tissue
PIXE;-;-
Ti
Ti
Saline solutions
Bone (rabbit tibia)
AE;ICP;L
XRF;-;- SIMS;-;-
U
Urine
TIMS;-;-
U
Urine
MS;ICP;L
U
U
Urine
Urine
MS;ICP;L
MS;ICP;L
U
Urine
MS;ICP;L
V
Zn
Zn
Serum, transferrin
Serum, nails
Plasma, hair, urine
MS;ICP;HPLC
AA;-;AA;F;L
MS;ICP;L
Zn
Zn
Zn
Liver tissue
Serum
Plasma, hair
MS;ICP;LA
AA;-;L
AA;-;-
Zn
Serum, hair and
lenses
Prostate tissue
AA;-;-
Zn
348
(continued )
XRF;-;-
Ref.
Se concentrations were determined by pulsed Zeeman-effect ETAAS
in blood plasma and erythrocytes from newborns to assess their Se
status according to birth weight and feeding type. Se intake was
inadequate in bottle-fed, small for gestational age, infants
Analysis performed by 3 independent laboratories using different
digestion and determination techniques suggested that the Se target
value of some batches of Seronorm Trace Element Serum Level 2
may be higher than stated
Selenotrisulfides of glutathione, cysteine and homocysteine were
synthesised and characterised by ES-MS and HPLC-ICP-MS. These Se
species were determined by HPLC-ICP-MS in liver cytosol of
exposed rats
See Cu, ref. 296
152
Double focusing SF-ICP-MS provided a better LOD (3 pg l1) than
ICP-MS with a hexapole collision cell (2 ng l1) for the determination
of the radionuclide 90Sr. For lower levels, an extraction procedure with
a crown ether resin was applied, giving a LOD of 0.4 pg l1 in urine
with natural Sr concentrations of about 1 mg ml1. Recovery of spiked
90
Sr in urine ranged from 82 to 86%
The levels of 232Th and 238U were determined in the urine of unexposed
Jordanians from 6 cities. 238U, but not 232Th, levels correlated with
age up to 60 years
PIXE was used to investigate the release of metals in tissues
surrounding metallic prostheses coated with biological glasses
to prevent corrosion
See Cr, ref. 132
No effect of surface roughness on Ti release from implants was
observed in in vitro and in vivo experiments involving SRXRF
and SIMS measurements of Ti in rabbit tibiae, 12 w and 1 y after
implantation
The amount of depleted U in the respiratory system of exposed soldiers
was estimated from a mathematical model based on the urinary
excretion of U isotopes
U was determined in urine, 10-fold diluted with 0.14 mol l1 HNO3, by
means of SF-ICP-MS. LOD was 0.2 ng l1 and RSD 5% at 10 ng l1.
Some vessel materials gave rise to high blank levels. Urinary U
concentrations were about 3–4 ng l1 in non-exposed individuals in
Belgium and the Netherlands, but a few (o5%) exceeded 10 ng l1
See Th, ref. 160
To assess exposure of war veterans to depleted U, both U
concentrations and isotope ratios in urine were measured by ICP-MS.
High resolution (4000) was required to resolve a polyatomic
interference causing apparent enrichment of 235U concentrations in
urine
235
U : 238U isotope ratios, at U levels of 5–20 pg g1, were determined
in urine, after sample decomposition and matrix separation, by means
of a single-detector magnetic SF-ICP-mass spectrometer, fitted with an
ultrasonic nebuliser. The uncertainty of measurement was evaluated as
2.5% (k ¼ 2)
See Fe, ref. 297
See Cu, ref. 286
In a study of 67Zn kinetics in premenopausal women, Zn concentration
and isotope ratios were determined in plasma, hair and urine after
digestion with H2O2 and dissolution in 1% HNO3. The conventional
cut-off value between normal and low Zn status (10.7 mmol l1 plasma
Zn) was confirmed
See Cu, ref. 37
See Cu, ref. 107
In pregnant women from Ankara (Turkey), both plasma and hair Zn
levels decreased significantly during the 2nd trimester. Plasma (but not
hair) Zn levels were significantly different between the ‘‘well nourished’’
and ‘‘poorly nourished’’ group
See Mg, ref. 299
The combined measurements of serum prostate specific antigen and Zn
in prostate tissue biopsies allowed improved separation between
prostate cancer and benign hyperplasia
312
151
296
153
160
48
132
154
157
159
160
313
314
297
286
315
37
107
81
299
52
Table 1
(continued )
Element
Matrix
Technique;
atomisation;
presentation
Zn
Hair
AA;F;-
Zn
Zn
Zn
Zn
Zn
Zn
Zn
Plasma, human milk
Liver
Serum
Nails, serum
Brain (rat)
Erythrocytes
Serum
AA;-;L
PIXE;-;AA;-;L
AA;-;AA;-;L
AA;-;AA;-;-
Zn
Zn
Erythrocytes, serum
Biological materials
(human blood and
hair, bovine liver and
muscle)
XRF;-;MS;ICP;LC
Various
Human organs and
tissues
Human biological
samples
Human central
nervous system
tissue
XRF;-;-
-;-;-
Various (4)
Clinical and
biological materials,
foods and beverages
Biological fluids
(urine, blood, human
milk, bile, saliva,
sperm)
Plasma
AA;-;-
Various (4)
Blood
AA;-;-
Various (4)
Serum
XRF;-;-
Various (4)
Serum, blood
Various (4)
Testis (rat)
AA;F;L
AA;ETA;L AA;;HG
MS;ICP;- PIXE;;-
Various (4)
Urine
AA;ETA;L
Various (4)
Serum
AA;-;L
Various (4)
Skin (cancer)
AA;-;L
Various
Various
Various
Various
MS;ICP;XRF;-;-
-;-;-
Ref.
Occipital hair samples, collected from 34 New Zealander adults, were
washed and digested with HNO3 prior to Zn determination by FAAS.
There was no evidence of seasonal variation or influence of food
intake, ethnicity, gender and hair colour
See Cu, ref. 108
See Cu, ref. 54
See Cu, ref. 65
See Cu, ref. 288
See Cu, ref. 289
See Cu, ref. 290
The prevalence of Zn deficiency among children attending primary
school in Turkey and its effect on anthropometric parameters
were investigated
See Cu, ref. 60
Zn isotope ratios were determined by high resolution multicollector
ICP-MS, after sample digestion and purification by anion exchange
chromatography. Comparison with SF-ICP-MS, indicated the
presence of 35Cl21 affecting accurate 70Zn measurements. The variation
of the 66Zn : 64Zn ratio in biological samples was investigated
A review of recent advances of in vivo XRF methods and their
applications to human organs and tissues was presented
The use of ICP-MS for stable isotope tracer studies in humans
was reviewed
Synchrotron microbeam XRF was used for the topographic and
quantitative analysis of selected elements in human brain and spinal
cord autopsy samples from deceased patients with neurodegenerative
diseases were compared with a control
The published literature on the analysis of clinical and biological
materials, foods and beverages using atomic spectrometric techniques
for the year up to the end of October, 2003, was reviewed
Analytical techniques and separation and/or enrichment methods for
the determination of organic and inorganic environmental pollutants
(and their metabolites) in biological fluids were reviewed
80
Plasma levels of Mg, Se and Zn (but not Cu) were lower in HlV1- and
2-positive Nigerians and decreased with CD4 lymphocyte count
reduction
In third-trimester gestational hypertension cases, blood Pb
concentrations, but not serum Ca (ionised and total), Mg or Zn levels,
were significantly correlated with blood pressure
Cu, Fe, Se and Zn were determined by TXRF in serum samples from
cancer patients and controls using the Compton peak as internal
standard. These data were used to assess the capabilities of various
artificial neural networks to classify individuals according to
their health status
Women, whose pregnancies were terminated as a result of a diagnosis
of neural tube defects, had lower serum Se and Zn levels and higher
serum Cu and blood Pb concentrations as compared to controls
Stage-specific and age-dependent profiles of Cu, Mn, Se and Zn in
rat seminiferous tubules were investigated by ICP-MS with a
microdissection technique and in situ elemental imaging by
micro-PIXE analysis
As, Co, Mn and Ni were determined in urine by simultaneous Zeemaneffect ETAAS, using Pd as the chemical modifier and atomisation at
2100 1C. Pyrolysis was carried out at 1350 1C in two stages, the first
using 5% H2 in Ar. Analysis of RMs gave 91–110% of the target
values. LODs were 0.78 (As), 0.22 (Co), 0.054 (Mn) and 0.35
(Ni) mg l1
In patients with malignancies, chronic inflammatory response (assessed
from plasma C-reactive protein concentrations) had no effect on the
levels of Cu, Mn, Se and Zn
In a prospective controlled study, the content of Cu, Fe, Se and Zn was
determined in acid-digested tissue samples from patients with
squamous cell carcinoma of the larynx or skin and controls. Fe and
Se levels, but not Cu or Zn, were significantly lower in patients than
in controls
108
54
65
288
289
290
162
60
161
44
22
46
1
2
70
67
56
66
316
61
69
68
349
Table 1
(continued )
Element
Matrix
Technique;
atomisation;
presentation
Various (4)
Serum
MS;ICP;FI
Various (5)
Blood plasma
AA;-;-
Various (5)
Arteries, cardiac
valves
Serum, milk, liver
and kidney
(dairy cows)
Blood, serum
AE;ICP;L
Various (5)
Various (5)
AA;-;L
Various (5)
Carcass, liver,
kidneys and brain
(rat)
AA;-;-
Various (6)
Heart, lung, kidney
(rat)
AA;-;-
Various (6)
Blood
XRF;-;-
Various (6)
Pus (human)
AA;-;L
Various (6)
Biological and
environmental
CRMs
AE;MIP;HG/
ETV
Various (6)
Biological samples
(SRMs)
AE;ICP;FI
Various (6)
Brain proteins
(human)
MS;ICP;LA
Various (7)
Urine
MS;ICP;L
Various (7)
Tendons, ligaments,
cranial and spinal
nerves
AE;ICP;-
Formalin-fixed
brain tissue
MS;ICP;L
Various (8)
Bone
AE;ICP;-
Various (8)
Biological CRMs
AE;ICP;L
18,17
Various (8)
350
AE;ICP;L
Ref.
An on-line dialysis system coupled with FI-ICP-MS was devised to
determine Cu, Pb, Se and Zn in serum samples using ID for calibration.
Samples were incubated with enriched isotopes for 24 h at 36 1C. From
1 ml serum sample, about 70% of the electrolytes were removed after
10 min dialysis, thus reducing polyatomic interferences. The precision
of isotope ratios was E1% for Cu and Zn and E2.5% for Se and Pb
Trace element (Cu, Fe, Mn, Se and Zn) concentrations,
malondialdehyde and total antioxidant capacity were evaluated in
patients with childhood asthma
The content of Ca, Mg, P, S and Zn in arteries and cardiac valves was
assessed in relation to age and ethnicity
Seasonal variations of Cu, Cr, Fe, Mn and Zn levels in biological fluids
and tissues of dairy cows from a rural and an industrial area in Turkey
were investigated
In a study of levels of blood Cd and Pb and serum Cu, Se and Zn
in samples from patients with coronary artery disease, blood Cd
concentrations were significantly correlated with indices of left
ventricular diastolic function
Suckling rats, exposed to Pb, were treated with the chelating agent
meso-2,3-dimercaptosuccinic acid (DMSA) and Ca supplementation.
Ca, Pb and Zn were measured in their carcass and Cu, Fe and Pb in
liver, kidneys and brain. Combined Ca and DMSA treatment during
Pb exposure caused a greater reduction in tissue Pb than either
treatment alone and had no effect on growth or essential element status
After total body irradiation, Cu and Fe (but not Mg, Mn and Zn)
tissue levels were significantly increased in kidneys, serum Ca and
creatinine were elevated and electron microscopic analysis showed
significant kidney tissue injuries
Br, Ca, Cu, K, Pb, Rb, S and Zn were determined in whole blood
samples from non-exposed Mexican subjects. Pb was determined after
sample digestion and Fe extraction in order to improve LOD
To investigate the host defence mechanisms mediated by the restriction
of the bioavailability of Fe and Zn in suppurative infection, Ca, Cu, Fe,
Mg, Se, Zn, lactoferrin and ferritin concentrations were measured in
human pus
HG and in situ preconcentration onto the (pretreated) interior wall of a
graphite furnace were combined for the simultaneous determination of
As, Bi, Ge, Hg, Sb and Se by MIP-OES with LODs of 3, 8, 15, 8, 20
and 10 ng, respectively, following high pressure or microwave-aided
acid digestion of the samples
The on-line separation and preconcentration of Bi31, Co21, Cr31,
Cu21, Y31 and Yb31 prior to determination by ICP-AES was achieved
using a FI system with a microcolumn of nanometer-sized TiO2 loaded
with 1-(2-pyridylazo)-2-naphthol. The adsorption capacity of the
system was 4.73, 18.57, 3.81, 6.14, 4.52 and 20.35 mg g1, respectively
Al, Cu, P, S, Si and Zn in human brain proteins were determined in
single protein spots by LA double-focusing SF-ICP-MS after
separation of protein mixtures by two dimensional gel electrophoresis
Two methods of sample preparation (dilution and acid decomposition)
for the analysis of As, Cd, Cu, Fe, Pb, Se and Zn in urine were
investigated. HCl concentration had a negative effect on signal
intensity, partially compensated by the use of internal standards
Age-related changes of the contents of Ca, Fe, Mg, Na, P, S and Zn
in tendons and ligaments and of Ca, Mg, P and S in the optic,
trigeminal, vagus, median, radial, ulnar, femoral, sciatic, tibial, and
common peroneal nerves were investigated by ICP-AES
25
In a retrospective study of the concentrations of Cd, Co, Cu, Fe, Mn,
Rb, V and Zn in formalin-fixed brain tissue from patients with
neurodegenerative disorders and controls, significant differences were
observed only for Cd and Zn
Eight trace elements were determined simultaneously in Bronze
age Cheshi human costa from China by ICP-AES after sample
dissolution with HNO3 and HCl. Analytical recovery ranged from 87%
to 107% and RSDs from 0.5% to 3.3%
The solubilisation of biological CRMs with a solution of TMAH in
CH3OH and ultrasonic shaking was reported as an alternative method
of sample preparation for the analysis of major (Ca, K, Mg, Na) and
trace (Cu, Fe, Sr, Zn) elements
72
19
252
74
317
64
58,
59
71
16
20
36
23
32
318
14
Table 1
(continued )
Element
Matrix
Technique;
atomisation;
presentation
Various (8)
Blood, serum, CSF
and urine
AE;ICP;L
MS;ICP;L
Various (9)
Herbal medicine(Echinacea purpurea)
AA;F;- AE;F;-
Various (9)
Teeth
XRF;-;-
Various (9)
CRMs, cultured
epithelial cells
MS;ICP;L
AA;ETA;L
AA;F;L
Various (9)
Liver, bile (rat)
AE;ICP;L
Various (10)
Brain (rat)
XRF;-;-
Various (10)
Biological CRMs
AE;MIP;Sl
Various (10)
Hair, nails, and skinscales
MS;ICP;-
Various (10)
Bone (rat)
AA;ETA;L
MS;ICP;L
Various (11)
CSF
XRF;-;-
Various (11)
Premature human
milk, premature
infant formulae
MS;ICP;L
Various (13)
Plaque deposits in
human arteries
MS;ICP;-
28,29
Various (15)
Medicinal plant
AA;F;L
Various (34)
Hair, drinking water
AE;ICP;MS;ICP;-
Various (56)
Blood, urine
MS;ICP;L
Various (68)
Soft (animal) tissues
(muscle, liver,
kidney, lung and
brain)
MS;ICP;-
Ref.
Al, Ca, Cu, Fe, Mg, Mn, Si and Zn were determined by ICP-AES or
SF-ICP-MS in blood, serum, CSF and urine samples from patients
with Parkinson’s disease and age- matched controls
The content and seasonal variations of Ca, Cu, Fe, Li, Mg, Mn, Ni, Sr
and Zn in different parts of Echinacea purpurea were evaluated by
principal component and hierarchical cluster analysis
The content of selected elements (Ca, Cr, Cu, Fe, Mn, Ni, Pb, Sr and
Zn) in the roots and crowns of both primary and permanent teeth
with caries disease was investigated
Ca, Cd, Cr, Cu, Mg, Mn, Mo, Na and Zn were determined in cultured
epithelial cells (Caco-2 TC7) by ICP-MS after closed vessel microwave
digestion. Method performance was evaluated by analysis of
CRMs and comparison with ETAAS and FAAS
The changes in concentrations of Al, As, B, Ba, Cd, Hg, Ni, Pb, and Ti
in the liver and bile of a hyperlipidemic rat model, after administration
of Sempervivum tectorum extract as a therapeutic agent,
were monitored
The concentrations of trace elements (Br, Ca, Cl, Cu, Fe, K, P, Rb, Sn,
Zn) in brain sections of 20 days old iodine-deficient and control rats
were measured by SR-XRF. The effect of perfusion with a 0.9% NaCl
solution before brain removal on the distribution of elements
was discussed
Slurry concentrations up to 1% m/v (particles o20 mm) were prepared
in 10% HNO3–0.01% Triton X-100 and introduced by means of a Vgroove, clog-free Babington-type nebuliser. The analysis of CRMs for
Ca, Cd, Cu, K, Mg, Mn, Na, P, Sr and Zn gave satisfactory results.
RSD ranged between 7–11%
As, Cd, Cu, Fe, Hg, Mn, Ni, Pb, Se and Zn were determined in
(microwave-aided) digested samples of hair, nails, and skin-scales from
subjects with As intoxication in West Bengal, India. Beside As, Mn, Ni
and Pb levels were high compared with values from the literature
The release of metals from different types of alloys implanted into rat
tibia was studied. The tissues near the implant were lyophilised and
acid-digested by microwave application. Fe concentrations were
determined by ETAAS and other metals (Al, Co, Cr, Nb, Ni, Ta,
Ti, V, Zr) by ICP-MS
Br, Ca, Cl, Cr, Cu, Fe, K, Mn, Ni, Rb and Zn were determined in CSF
of patients with amyotrophic lateral sclerosis and controls. Two
methods of sample preparation were tested in order to improve LODs
Al, Cd, Co, Cr, Cu, Fe, I, Mn, Pb, Se and Zn were determined, by ICPMS with an octopole reaction cell, in premature human milk
samples and premature infant formulae after microwave-aided
digestion. LODs ranged from 0.5 to 11 ng g1. The content of
essential elements differed between human and formula milk
The concentrations of Al, Ba, Ca, Cu, Fe, K, Mg, Na, P, Pb, S, Si
and Zn in soft and calcified plaque deposits in human arteries were
determined by ICP-MS. S levels (23–140 mmol g1) were interpreted
as homocysteine. The Ca:P molar ratio was not explained as
hydroxyapatite and other forms of Ca and P (e.g., phospholipids) may
contribute. In the calcified deposits, the concentrations of Ca and P
were at least an order of magnitude higher than those in the soft plaque
26
The total content and water soluble fraction of Al, Ba, Ca, Cd, Co, Cr,
Cu, Fe, K, Mg, Mn, Na, Ni, Pb and Zn were determined in different
parts of Azadirachta indica (L) Neem by FAAS
34 elements were determined in drinking water and hair of women from
an acid and an alkaline area in southern Sweden and their levels
compared. Ca, Mo, Pb and Sr levels in water and hair were positively
correlated
After a firework explosion, two rapid screening methods were
developed for the determination of 56 elements in diluted blood and
urine. Quality control procedures and advantages and limitations of
the methods were discussed
Sixty-eight elements were determined by double-focusing, SF-ICP-MS
in soft tissues, after microwave-assisted digestion with HNO3. RSD
was o5% in most cases. Only for Cl were significant differences from
the target values of CRMs observed. For elements at concentrations
42 mg g1, results were compared with ICP-AES
167
55
33
319
47
15
76
34
57
27
165
82
24
31
351
prevention of cancer trials between 1981 and 1996. Yeast-based
materials with a high proportion of the total Se as SeMet
produced larger increases in plasma Se in the subjects participating in the trials. However, when a yeast-based supplement
was compared with simple synthesised SeMet alone, higher
blood Se concentrations were given by the yeast material,
pointing to other factors influencing the bioavailability.
3 Analysis of foods and beverages
The following sections discuss developments with foods and
beverages. In addition we include related topics such as the
influence of processing and packaging on food items, which are
not covered in any of the other Atomic Spectrometry Updates.
Our last review was published in April 2004.1 Other reviews
seen in the last year referred to characterisation of beverages
with reference to elemental speciation and isotopic ratios174
and ten years of European experience with official methods for
measuring stable isotopes in foods for the detection and/or
prevention of fraud.175 Pyrzynska176 reviewed sample preparation and analysis in a discussion of adventitious contamination, regulatory limits and authentication of wine samples.
Contamination of rice led to epidemics of severe Cd toxicity
in Japan in the 1960s and 1970s. Ikeda et al.177 have reviewed
the decrease in concentration of Cd in rice as a consequence of
environmental improvements during the last 30 years.
3.1 Sampling and sample preparation
3.1.1 Extraction. Improved efficiency of analyte extraction
when applying ultrasonication was demonstrated by several
workers.178-183 Compared with non-sonication or with digestion, extraction was much quicker and simpler and gave similar
results with a variety of sample types and analytes. Alkaline
extractions were occasionally employed including the very
simple expedient of using 0.1 M NaOH to obtain Se compounds from onion,184 but an unusual approach was taken by
Vela and Heitkemper,185 who used trifluoroacetic acid at
100 1C in what was described as a ‘mild’ procedure to extract
As from infant foods.
Those with an interest in speciation are concerned with
extraction efficiency and also with showing that there is no
redistribution of the element during the extraction or on subsequent storage. These are features which appear to be influenced not just by the extraction procedure but also by the
elements and food types that are investigated. Using a simple
aqueous procedure only 68% of the total Se was obtained from
mushrooms186 and as little as 9% from yeast tablets.187 A cold
water extraction of lyophilised or fresh garlic yielded Se-allins
(Se-alk(en)yl-L-cysteine selenoxides) that disappeared when
stored at 44 1C. Curiously, the allin was stable when extracted
from fresh onion.188 Four different extraction procedures were
evaluated by Huerta et al.189 for the quantitative recovery of Se
species from a BCR CRM cod muscle. The species were
subsequently separated by reversed-phase and size-exclusion
HPLC and Se detected by ICP-MS with an octopole reaction
system using H2 to eliminate isobaric interferences from Ar
species. The highest recoveries of Se were obtained using
enzymatic digestion, whereas ‘soft’ extraction with CH3OH–
HCl recovered only 5% of the total tissue Se. With three
consecutive 50% v/v CH3OH–HCl extractions, quantitative
recovery of As species from rice, fish and chicken was possible.
The species in the rice extracts were stable for at least three
months whereas AB in the other samples was gradually
transformed to DMA.190 Extractions using CHCl3–CH3OH
were successfully employed to obtain stable As species from
baby foods191 and nuts.192 Attempts to extract As species from
peanut butter into CHCl3 with CH3OH were unsuccessful but
much better recoveries were given with 2-butoxyethanol.183
352
Enzymic hydrolysis to release As species from the protein
matrix of food samples was occasionally implemented.191,193
3.1.2 Digestion. A method that reduced the residual C to less
than 1.3% was developed by Flores et al.3 Samples were
wrapped in paper, placed on a quartz holder and inside a
quartz vessel. After addition of an NH4OH solution to the
paper, the vessel was pressurised with O2 and microwave
radiation applied for 20 s at 1400 W. When reflux with
HNO3 was then applied the residual carbon was less than
0.4%. Since most analytical techniques have long been able to
cope with samples having much greater levels of carbon the
requirement for this procedure is unclear. Variations on the
typical microwave-assisted acid digestion theme were presented. Trevizan et al.4 described a PTFE support so that
bovine liver within glass cups could be digested by acid vapour
within a microwave oven. In the method developed by Chen
et al.,127 samples were digested using TMAH with focussed
microwave heating and the methylmercury extracted with
n-heptane after addition of Cu21 and derivatisation with
sodium tetrapropylborate. Simple immersion of biscuit samples in acid with C2H5OH, at room temperature, was reported
to provide results for Fe and Zn by FAAS that were comparable to those achieved after digestion with heating.194 By
comparison, a mixture of H2SO4–HNO3–H2O2–HF–V2O5
was taken to digest vegetables before measuring Se.195
3.1.3 Preconcentration. No major innovations for analyte
enrichment were introduced in the last year. One piece of
original work involved the use of silica membrane discs
modified by 1-hydroxy-2-(prop-20 -enyl)-4-(prop-20 -enyloxy)9,10-anthroquinone to trap Cu21 ions from a range of SRMs.
The adsorbed analyte was then eluted with HNO3 and an
enrichment factor of around 400 was reported.8 Less spectacular results were obtained when tap water was taken through
a column of naphthalene–methyltrioctlyammonium chloride,
which adsorbed Cd as the CdI42 ion. After optimisation of
pH, iodide and flow conditions a 40-fold preconcentration was
achieved and the LOD using FAAS was 0.6 ng ml1.196 Other
applications involved conventional column approaches either
off-line or on-line in FI pathways. Ion-exchange resins, activated carbon and chelating resins were all employed as solid
phases with measurements of metals in drinking water, beer
and wine.196-200 Fernandes et al.200 evaluated C18 bonded silica
gel and powdered polyethylene as sorbents for Cd, Cu and Pb
in wine, with ammonium diethyldithiophosphate as the complexing agent. Slightly better performance was found with the
C18 for Cu and Pb and with polyethylene for Cd. A preconcentration factor of more than 300 was reported with a simple
cloud point extraction applied to the measurement of Pb in
water.201
3.2 Speciation
In contrast to previous years most of the published work
referring to speciation concentrates on the results of analyses
rather than technical developments. Such work is discussed in
later sections of this review. Furthermore, much of the work
relates to the sample preparation and is designed to avoid
changes during extraction (see 3.1 above). Yet again it is As and
Se that dominate the interest in speciation. While many of the
speciation procedures involve LC-ICP-MS some other interesting approaches were attempted. Ecinar et al.202 opted for
SEC with combined matrix-assisted laser desorption ionisation
TOF-MS and ES-quadrupole-TOF-tandem-MS to determine
selenoproteins in yeast-based food supplements. Organoselenium species in yeast, mustard and garlic were separated by
GC and MIP-AES using a specially designed system that also
involved SPME.203 This method gave results within 3 min with
sub-ppb LODs. Reversed-phase HPLC and SEC were used to
separate Se species from cod muscle. Measurement involved
post-column ID and an octopole reaction cell with determination of the 78Se : 77Se ratio.189 Simon et al.204 were interested
in the effects of the mobile phase on post-column photooxidation and HGAFS of As species from fish and seafood samples.
They found that widely used aqueous pyridine solutions inhibit
post-column conversion to detectable As, with loss of sensitivity. Revised conditions were shown to give good separation of
AB, AC, TMAO and TMI with LODs of 4–12 pg. In an
investigation of human milk, Mn compounds were identified
by SEC-ICP-MS.123 The procedure does not allow for an
impressive sample throughput as the main peak appeared at
95 min. A classically simple method for differentiating the (IV)
and (VI) oxidation states of Se and Te ions was reported by
Cava-Montesinos et al.205 Milk slurries were sonicated with
aqua regia and immediately measured by AFS to determine the
quadrivalent species. Similar samples were reduced using KBr
to determine total Se and Te concentrations.
3.3 Applications using hydride generation
Arsenic was measured in fish and coffee beans by FI-HGAAS,
with a method validated using CRMs. Reagent concentrations,
atomisation temperature, injection volume, reaction coil length
and carrier flow rate were all optimised. Interference from
other ions was masked with ascorbate and KI in HCl. The
method had an analysis rate of 135 samples h1. Several
workers have reported on the analysis of Chinese medicines
using hydride generation AFS for As170,206 and As and Sb.171
All included details of how the procedures need to be optimised
to give satisfactory results. For the analysis of milk, also by
AFS, Cava-Montesinos et al.207 found that KBr was the
preferred reductant for Se and Te while ascorbate–KI was
better for As and Sb. Either reductant could be used for Bi.
3.4 Applications using flame atomic absorption spectrometry
In the 2004 ASU1 we mentioned an innovative accessory that
produced a dry aerosol for introduction of solid powdered
CRMs into the flame. The same workers have now reported on
the use of this technology for the measurement of Cu in
medicinal plants by flame atomic absorption spectrometry.
The LOD was 1.2 mg g1 from a 1 mg sample and results were
not different from those reported after digestion and conventional FAAS.6 Aleixo et al.208 measured Cd and Pb by beam
injection FAAS. In this technique a nickel-base alloy tube is
positioned above the burner, in the light path. A pressurised
aerosol of a fixed volume of a liquid sample is forced into the
tube, through a small inlet, where atomisation takes place.
Samples were prepared by HNO3 extraction from dried powdered foods. The LODs were 0.03 mg g1 and 1.6 mg g1,
respectively, representing improvement factors of 20 and 26.
Good agreements with certified values were reported for
several RMs. Zinc was determined in milk powder and infant
formula, using an FI system that included the sample dissolution process179 and gave an LOD of 0.3 mg g1.
3.5 Applications using electrothermal atomic absorption
spectrometry
There are few reports of non-graphite atomisers being used.
Amin et al.209 employed a molybdenum tube for measuring Cd
in vegetables. Slurry samples were prepared in 10% glycerol
and thiourea was used as the modifier. An LOD of 13 fg was
obtained. The tungsten coil atomiser has slipped in popularity
in recent years and just one application was seen. Measurement
of As in an oyster CRM was described and Ir or Rh were
the preferred modifiers.94 Optimisation of all conditions was
presented.
Aleixo and Nobrega210 showed that dilution of milk with a
mixture of tertiary amines (10% CFA-C) improved the handling by the autosampler with a useful effect on repeatability.
Details of modifier, heating temperatures and calibration were
also reported. The positive features of permanent modifiers
were further exploited, particularly using Ru alone or with Ir
or Zr. A Brazilian group investigated such modifiers for
measuring different elements in cachaca, a spirit derived from
sugar cane,211,212 and in drinking water.213 They reported the
effects on LODs, characteristic concentrations and peak
shapes. However, they noted that for Al, Cd and Pb the matrix
of cachaca itself acts as a modifier and addition of other
chemicals is not necessary.212
Calibration methods were investigated for the measurement
of Mn in vitamin-mineral tablets by a solid sampling assay.214
Experimental parameters were optimised and calibrations with
aqueous standards, aqueous standards added to solid sample
and against solid CRMs were compared. The best results were
obtained using the aqueous standards with results that were in
good agreement with those determined after acid digestion.
Because of the volatility of Hg, measurement of this element by
ETAAS usually warrants attention to see how the drying and
ashing were accomplished without loss of analyte. For measurement in wine Karadjova et al.215 complexed the metal with
APDC and an LOD of 0.2 mg l1 was reported.
3.6 Applications using inductively coupled plasma-mass
spectrometry
Two projects were concerned with non-standard sample introduction methods and both involved the analysis of rice flour. In
one, laser ablation was used with no sample preparation
required. Three different CRMs were taken for calibration in
the measurement of Cd and no interferences were observed.216
In the second piece of work ETV was chosen with Cd, Cr, Cu,
Hg and Pb being measured.217 Samples were prepared as
slurries and the analyte ions were transported through a
DRC containing NH3. Ion signals were enhanced by addition
of ascorbate to the samples. Both ID and standard additions
were used for quantitation and each approach gave results that
were within the certified ranges. An octopole reaction cell was
used to remove polyatomic interferences when measuring 11
essential and toxic elements in premature human milk.27 The
organic matrix was destroyed by digestion prior to analysis.
Operating parameters (octopole bias and quadrupole bias)
were optimised so as to form a ‘potential energy barrier’
between the cell and the quadrupole mass spectrometer and
the LODs were from 0.5 to 11 ng g1. Multiple collector ICPMS was employed to determine Sr isotope ratios in Emmentaltype cheeses. 83Kr, 82Kr and 85Rb were measured to correct for
interferences. The 88S : 86Sr, 82Sr : 86Sr and 84Sr : 86Sr ratios
were determined with precisions (RSD) of 0.002–0.01% and
the measurement uncertainty was calculated to be 0.016%.218
Apart from these studies there was remarkably little to report
that was in any way new.
3.7 Applications using other analytical techniques
Resonance ionisation MS, with an electrothermal atomiser, was
applied to the measurement of Co in the juices from a number
of different fruits.219 The wavelength chosen was 298.71 nm
and the LOD was less than 5 pg. A calibration range of up to
1 ppb was produced and the amounts of Co in 5 ml of pear,
apple and mandarin orange juice were found to be 150, 45 and
100 pg, respectively.
New applications of XRF continue to appear. A Brazilian
group used SRTXRF for multielement analysis of wine348 and
mineral waters.220 Samples of about 10 ml were simply dried on
a perspex holder and irradiated for 200 s. Food samples were
analysed by TXRF,178 EDXRF221 and WDXRF222 following
353
minimal sample preparation. The results compared well when
assessed against other analytical techniques.
In addition to determining the hydride forming elements,
AFS is ideally suited for measuring Hg following cold vapour
generation. Cava-Montesinos et al.223 developed a procedure
which allowed a rapid analytical rate (70 samples h1) and used
about 15% of the reagent volumes compared with conventional techniques. The LOD was 0.011 ng g1 and the RSD was
3.4% at 0.3 ng g1 in milk. An LOD of 0.03 ng ml1 was
reported for a method that involved digestion of medicinal
plants in closed vessels prior to AFS.169 Gomez-Ariza et al.224
used AFS coupled to capillary GC to measure methylmercury
in seafoods. Two procedures were investigated and the most
effective parameters determined. One, where small samples
were taken and both the inorganic and methylmercury were
ethylated, required no further clean up. In the second, using
larger samples, alkylated species were extracted into organic
solvent.
Few reports mentioned atomic emission spectrometry and
where this was so, with ICP225 or with MIP,14,15,203 the
technique was incidental to the sample preparation.
3.8 Progress for individual elements
3.8.1 Arsenic. There was much work which simply reported
on the concentrations of As in different foods and total
diets226,227 for which HGAFS and HGAAS were employed.
Chemical modifiers for use with the tungsten-coil atomiser
were investigated: Ir and Rh were effective but Pd was not.94
However, most of the recent analytical literature was concerned with aspects of speciation; the extraction, chromatography and measurement. The usual detectors are ICP-MS with
ion exchange columns, either anion- or mixed anion/cationexchange columns used for the separations. With most systems
the species AsIII, AsV, MMA, DMA and AB were differentiated, and while most or all were present in foods the proportions varied considerably.183,190,192,193,228,229 It was suggested
that the ratio between the AsIII and AsV in soil or water
influences the concentrations and species found in the foods.228
Interest in the As content of infant foods was evident. Many
contain very low concentrations, less than 24 ng g1,185 mainly
as AsIII, AsV and MMA. However, when foods contained fish
AB was detected and the concentrations were much higher at
2–3 mg g1.191 Since AB is the main As species in marine fish
this is not surprising, an observation confirmed by Kato
et al.,230 who analysed sardines, Japanese sandfish and squid.
However, when they examined the fish sauces prepared from
these they found that most had been converted to DMA.
The concentration of As in drinking water reduced on
storage due to the formation of As/Fe precipitates.231 Addition
of EDTA–CH3COOH prevented this loss.
3.8.2 Lead. There were no analytical developments to mention and relatively few reports of measurements in foods. One
interesting study was of the toxicokinetics of Pb in blood and
cows milk.232 Animals were given a single i.v. dose of Pb at
differing intervals (up to 20 h) after the onset of light and
specimens were collected at time points thereafter to calculate
the elimination half life and area-under-the-curve. Data
showed that transfer of Pb into milk differs throughout the
day. Samples of fish from Nigeria had Pb concentrations that
were associated with proximity to the roads near the markets
where they were sold.233 Total dietary intakes in children and
adults were determined in Germany234 and Pb in illicit alcohol
in the USA was reported.235
3.8.3 Mercury. Measurement of Hg in wines was described
in two papers. In one, a special reactor was designed to pretreat the samples with O3 prior to analysis by FI-CV-AAS.236
354
This provided for a rapid determination compared with other
preparative methods. The second involved complexation with
APDC and extraction into an organic solvent followed by
ETAAS.215 The LODs for the two methods were 0.5 mg l1 and
0.2 mg l1, respectively, while the first was a little more precise.
Gas chromatography was included in methods for measuring
methylmercury in fish and seafood. Chen et al.127 elected to use
microwave assisted TMAH extraction and derivatisation with
sodium tetrapropylborate. The product was extracted into
n-heptane and analysed by GC-MS with an LOD of 40 ng
g1. Two methods applicable to different concentration ranges
were developed by Gomez-Ariza et al.224 In the first, for 0.75–
10 mg Hg g1 dry weight, clean-up was not necessary because of
the small sample weight required. Both inorganic Hg and
methylmercury were ethylated, methylmercury separated by
capillary GC and the Hg detected by AFS after pyrolysis. The
second method was similar, but for lower concentrations, 6–
1000 ng Hg g1 dry weight, and required a clean-up stage to
remove interferents from the matrix. The appropriate method
could be selected after a preliminary screen for total Hg, as
most of the Hg in seafood is methylmercury. Optimal parameters for both approaches were evaluated and the methods
evaluated by analysis of two CRMs. The normal daily intakes
of Hg by children living in a German community were measured as part of an extensive project.226
3.8.4 Selenium. As in recent years Se is the element that
attracts the greatest attention, with the majority of reports
referring to speciation and most of these involving the Se-rich
varieties of either yeast or garlic (see section 2, above). Despite
the plethora of published methods from the last five years, yet
more are appearing. In addition to HPLC with ICP-MS, TOFMS, ES-MS,202 GC-MIP-MS203 and CZE-ICP-MS187 have all
been employed. One of these reports was essentially a review of
all the analytical phases for a speciation analysis.202 However,
there are now also reports where the emphasis is on the
measured concentrations in foods rather than just dealing with
the analysis itself. The impetus to this appears to be the interest
in Se and the prevention of cancer. Certain foods are being
prepared with enriched concentrations and the clinical studies
require knowledge of the concentration and of the forms of Se
that are present.173,188 Total dietary intakes of Se were reported
for children in Germany226 and Se concentrations were given
for infant milks,237 vegetables,195,238 and various other
foods.239
3.8.5 Other elements. There were few reports of other elements to which attention needs to be drawn. Foods available in
Slovenia were analysed by ICP-AES to determine Al.240 High
concentrations were found in mussels, parsley and lamb’s
lettuce (300–400 mg kg1 dry weight), but most items contained less than 30 mg kg1. These authors also showed, like
others before them, that Al is leached from cookware into
acidic foods. It is not often that Co is determined in foods.
Saulea et al.241 analysed a large number of different foods and
beverages for this element using ETAAS. Samples were prepared by acid digestion and standard additions were necessary
for calibration. It has been shown in the past that soy-based
infant milks and foods contain very high concentrations of Al.
Cockell et al.242 now report that Mn is present in soy and rice
infant beverages. They calculated that the daily Mn intake for
infants up to 1 y of age is at or above the Tolerable Upper
Intake Level and warn that such beverages should not be used
as they may present an increased risk of neurological damage.
3.9 Single and multi-element analysis of foods and beverages
3.9.1 Dietary intake studies. Two further publications have
appeared from the group who collected 7-day duplicate diets
from children in Amrun, an island at the north of Germany.226,234 The intakes of As and Hg were 0.89–6.75 and
0.06–0.62 mg kg1 body weight week1, while Pb was 0.04–1.6
mg kg1 body weight d1, all well below WHO limits. However,
the age-related targets set by Austrian, German and Swiss
Nutrition Councils for Se intakes were not met in a significant
proportion of the children. These workers also measured Pb in
the diets of children and adults from a highly industrialised
part of Germany and the intakes were similar to those of the
Amrun children.234 In a third paper, this group determined the
very low Au and Pt intakes in children aged 14–83 months.
Concentrations of Pt were slightly higher in supermarket
products compared with garden grown vegetables.243 Akhter
and co-workers measured Ca, Sr and U in Pakistani diets244,245
as part of a programme related to radiation protection.
According to the recommendations of the International Commission on Radiological Protection (ICRP), typical diets have
adequate Sr but only about 60% of the necessary Ca. The U in
food, at 2.3–11 ng g1 dry weight, gives daily intakes that are
said to be 40% higher than the ICRP value but within the safe
dose limit for radioactivity.245
The Cu, Fe and Zn contents of foodstuffs were evaluated in
Nigeria246 and in Chile.247 The foods examined and the concentration units reported were not the same so cannot be easily
compared. The Chilean study was particularly thorough and
daily intake data were reported for all three elements in age
related groups from infants through to 64 years, for both male
and female subjects. The authors noted that infants and
women of reproductive age are liable to Fe deficiency, all
groups are at high risk of Zn deficiency and adults have a
moderate risk of Cu deficiency. In a more ambitious project
nine elements were determined in foods consumed in Rio de
Janeiro.248 No problems were evident for toxic elements but Cr
and Zn intakes were below the recommended allowance. It was
noted that black bean is a good source of Cu, Mn, Ni and Zn.
Daily intakes of Cr, Ni and Se by adult Poles were found to be
60–90, 1.24–166 and 54–99 mg, respectively.249 In another
Polish study, B was determined in diets of children.250 There
are few previous indications relating to this element in foods,
making this a useful source of information. The daily intakes
were 1.01 and 1.2 mg for pre-school children and teenagers,
respectively.
Ikeda and colleagues177 presented a review of dietary exposure to Cd, as published during a period of more than 30
years since the early 1970s, in environmentally polluted and
non-polluted areas of Japan. Following soil remediation, concentrations in Japanese rice had fallen from around 600 mg d1
to less than 30 mg d1. Nevertheless, at the time when the
review was puiblished (2004), it was still higher than in rice
from other parts of Asia.177
3.9.2 Human milk and infant foods. Mechanisms for the
transfer of essential and non-essential elements into human milk
are still poorly understood. Domellof et al.108 found that Cu,
Fe and Zn in human milk have no association with the
maternal status of these elements and suggested that this
indicates active transport in the breast tissue. In addition, they
compared the Cu, Fe and Zn concentrations in samples from
Swedish and Honduran mothers. They found that the Fe was
higher but Cu and Zn were lower in the Swedish samples. By
contrast, the concentrations of Hg and Pb in human milk were
found by Dorea117 to be directly proportional to those in
maternal blood, indicating no control of movement across
the mammary membranes. Concentrations of Se in human
milk were reported from Spain237 and Italy146 and were similar
to those found in other countries. Distribution of Mn among
the protein and lipid fractions in human milk123 and a panel of
more than 10 elements in premature milk251 showed that there
are considerable differences within milk in addition to the
temporal changes that have long been recognised. The work
on As in infant foods185 and Mn in soy and rice beverages242
was described above (sections 2.8.1 and 2.8.5, respectively).
3.9.3 Milk and dairy products. An investigation of Cr, Cu,
Fe, Mn and Zn in cows farmed in an iron–steel processing
region and in a non-industrialised area showed that, as for
human milk, the concentrations of essential elements in bovine
milk are not affected by maternal status.252 Much more
important are the changes that occur during processing, as
shown by Closa et al.253 Skimming led to increases in the
concentrations of the eight minerals measured, especially of
Ca. Further increases took place in the production of yoghurt
following the addition of milk solids, evaporated milk or
ultrafiltrates. The normal concentrations of As, Bi, Sb, Se
and Te in Spanish,207 and of Cd, Cr, Cu, Pb, Se and Zn in
Cantabrian (Italy) milks,254 were reported.
3.9.4 Wheat, flour and rice. Fifteen different elements were
measured in wheat purchased in Egypt, Saudi Arabia, Yemen,
Oman, Dubai and Australia.255 The concentrations of 36
elements, later limited to 15, in varieties of barley were
determined to investigate associations with genotype, plant
stage of growth, and soil type.256 Inorganic As in 40 samples
of American white rice ranged from o0.025 to 0.271 mg g1
wet weight.257 Interesting analytical developments with ICPMS, where rice flour CRMs were used to validate the work,
were mentioned in section 2.6.
3.9.5 Vegetables, nuts and fruits. Over the years, transfer of
Pb from soil and dust to crops has been measured in several
studies. Although pollution from petrol and industrial sources
is now reduced, this topic is still studied, yielding essentially the
same conclusions. The most recent piece of work found highest
concentrations in root (root : soil ratios of 0.02–0.51) with less
in shoots and very little in leaf or vegetable fruit. The ICP-AES
technique used, however, had an LOD of 10 mg g1 dry weight,
and may not be sufficiently sensitive to provide as complete a
set of information as is really required.258 Analysis of shiitake,
the most popular edible mushroom in Eastern Asia, showed
that Se was present as SeMet, possibly bound to a large soluble
protein.186
The As in different types of nuts was measured.192 Most was
present as AsIII and AsV, 0.07–12.7 and 0.5–4.3 ng g1,
respectively, while As as MMA was at 0.1–1.3 ng g1. Very
low concentrations of MMA were found, up to 0.5 ng g1 in
pistachio nuts.
At 0.0462 mg 100 g1 and 0.046 mg dl1, the Zn in grapes
and grape juices consumed in Spain is lower than reported in
popular food composition tables. The mean Cu values in the
same samples were 0.0515 mg 100 g1 and 0.0063 mg dl1.259
3.9.6 Fish and seafood. As part of a long-term monitoring
programme 18 elements, including As, Cd, Hg and Pb, are
being measured in economically important fishstocks from the
Barents, North and Norwegian Seas. The programme commenced in 1994 and is expected to continue until at least 2010.
No undue concentrations have been found.260 Conversion of
AB to DMA during the production of fish sauce was referred
to in section 2.8.1 but a study of fish caught in an estuary in
Thailand demonstrated that in some situations inorganic As
can be present in vivo.193 Water draining from a tin mining area
was contaminated with As and sediments had total As concentrations up to 269 mg g1 (dry weight), with some AsIII but
mostly as AsV. Fish contained AB, as expected, but inorganic
As was also found. Dried fish sold in an open market in Nigeria
had Pb at 8–12 mg kg1, caused by contamination from
adjacent traffic exhausts.233
355
3.9.7 Drinking waters and non-alcoholic beverages. A new
twist has been added to the problem of high concentrations of
As in drinking water in Bangladesh. It has been suggested, on
the basis of in vitro work, that Sb may be a confounder in the
development of As toxicity. However, analysis of 245 well
water samples, with As concentrations of o1 to 747 mg l1, all
had Sb at o1 mg l1, suggesting that this potential danger is
not relevant to this region of the country.261 High concentrations of As in drinking water are found in other countries and
values of up to 3 mg l1 were reported from Turkey.262 This
compares with a maximum allowable level of 0.05 mg l1. The
importance of appropriate conditions for collection and storage was demonstrated by studies in the USA and was discussed in section 2.8.1. A number of popular soft drinks
manufactured and sold in Pakistan were analysed by Wattoo
et al.263 Of the 15 elements measured Al, Cd, Fe, Ni and Pb
were found at concentrations above the WHO drinking water
limit. Many also showed evidence of microbiological contamination. Selenite and selenate in drinking water were separated
and individually measured by ETAAS in an FI system developed by Stripeikis and co-workers.198 Measurement by
ETAAS made use of Ir as a permanent chemical modifier. A
systematic study with Ir, Rh, Ru and Zr, to determine the best
permanent modifier for each element (Al, Cd, Cr and Pb) in
drinking water, was carried out by Pereira et al.213 It was found
that Rh was best for Cd and Cr while Zr was appropriate
for Al and Pb.
3.9.8 Alcoholic beverages. Analysis of wines for purposes of
demonstration or investigation of their provenance is discussed
in section 2.11, below. The way in which the vinification
processes alter the trace element composition of wines has been
described in previous Updates. A further study has looked at
the preparation of German white wines.264 Total Sr concentrations increased in Portuguese wines throughout each stage of
the process.265 It was also shown that the 87Sr : 86Sr ratio
remains unaltered and is identical to that of the soil in which
the grapes were grown. Following reports of increased blood
Pb concentrations in subjects drinking illegally produced spirits (moonshine), 115 samples collected from nine states in the
USA were analysed. Concentrations found were from 0 to
53 200 mg dl1, with a median of 44.0. The limit proposed by
authorities of 300 mg dl1 was exceeded in 28.7% of the
samples. It was calculated that sustained intake of large
amounts of many examples of moonshine would cause blood
Pb concentrations to exceed 25 mg dl1.235 By contrast, the Pb
in Korean wines, at 5–87 mg l1 appears quite innocuous.
Concentrations of Cd were also very low at o0.1–3.0
mg l1.266 In samples of Brazilian sugar cane spirit, Cachaca,
the concentrations of Al, Sb, Cd and Pb were r22.4, r39.1,
r0.7 and r526 mg 11, respectively, and 0.64–1.53 mg l1 for
Cr.211,212
3.9.9 Other foods. Trace elements in various other foods
were reported. A large number of herbs, spices and condiments
from Turkey267 and Sri Lanka221 were analysed to determine
whether the nutritional properties might be related to their
mineral content but no unexpected results were obtained. The
usual major elements were found at large concentrations while
trace elements were low. High levels of Al were reported in a
number of samples but contamination-free determination of
this element requires considerable care and attention. Eggs as a
source of trace elements are not often considered. Some quite
high concentrations were determined in a study from Nigeria
and the authors drew particular attention to the Cd and Pb.268
The As species in chicken meat and in peanut butter were
determined in two separate projects. Both samples were being
investigated as candidate RMs. The chicken meat contained
DMA and AB at concentrations of 106 and 37 ng g1,
356
respectively229 while, in the peanut butter,183 AsIII, AsV,
MMA and DMA were measured at 1.6, 6.3, 4.9 and 6.1 ng g1.
3.10 Reference materials and collaborative trials
Very little work relating to new food reference materials has
been presented. A rice material was prepared for the International Measurement Evaluation Programme (IMEP) where
Cd, Cu and Pb were certified using ID-ICP-MS as the measurement technique.269 It was found that a digestion procedure
with HF was necessary to ensure complete solubilisation. The
SI-traceable concentrations found were 14.39 106 mol kg1,
44.31 106 mol kg1 and 2.034 106 mol kg1 for Cd, Cu
and Pb, respectively. Measurement uncertainty was estimated
according to ISO guidelines and the calculated combined
uncertainties were also reported. The rice powder was observed
to be hygroscopic and a second series of measurements were
carried out after equilibration of the material with ambient
moisture conditions. Results from the analysis of chicken meat
and peanut butter candidate RMs were discussed in the previous section (3.9.9).
3.11 Packaging and cooking
It has long been recognised that packaging materials may
contribute considerable contamination to foods. Modern materials are less likely to offer risks to health but it is necessary to
be vigilant. A classic situation is that of foods in tin cans and
instances of gastrointestinal disturbances are well known.
Although cans are now coated with a lacquer, some migration
is possible with acidic foods. Using randomised double-blind
crossover studies, Boogaard et al.270 compared the incidences
of adverse gastrointestinal effects in volunteers given different
concentrations of Sn either as tin(II) chloride added to tomato
juice or Sn migrated from cans into tomato soup. Their
findings indicated that it was the chemical form of Sn rather
than the elemental concentration that determined the severity
of adverse effects. Some 50–60% of Sn in tomato juice was in
the form of low Mr species, whereas this fraction constituted
only 31–32% of Sn in the tomato soup. A dose relationship
was only observed for SnCl2 added to tomato juice and no
clinically significant adverse effects were observed in volunteers
given that Sn migrated from cans. They considered that the
current recommended levels of 200 mg kg1 Sn for canned
beverages and 250 mg kg1 Sn for canned food are safe levels
for adults in the general population. Polyethylene materials are
used extensively for packaging many types of foods yet the
content of potentially harmful elements has not been well
documented. Three such materials were digested using HNO3
and H2O2 before analysis for As, Cd, Cr, Pb and Sb by ICPTOF-MS.271 The highest concentrations obtained were 0.33
mg kg1 Cr, 1.06 mg kg1 Pb and 1.81 mg kg1 Sb. Other
elements were below the LODs and in some samples none of
these 5 elements could be detected.
The effects of soaking and boiling peas on concentrations of
Mo, Ni, P and Zn were thoroughly investigated. Soluble high
Mr species were lost so that while the total concentrations were
reduced, the overall proportion of ionic and labile complexes
increased.272 Yet another study confirmed the observation that
acidic foods cooked in aluminium utensils will extract the
metal. This time sauerkraut and sour turnips were shown to
be the villains.240
3.12 Authentication of foods: provenance and origins
Determining the elemental composition of foods and beverages
to authenticate their origins has been regularly reported in these
reviews, especially for wines. Following from the original measurements, concentration patterns of specific suites of elements
and/or isotopes have been proposed as being indicative of the
Table 2
Foods and beverages
Element
Matrix
Technique;
atomisation;
presentation
Al
Sugar cane spirit
AA;ETA;L
Al
Foodstuffs,
cookware
AE;ICP;L
As
As
Drinking water
Foods
-;-;L
AA;F;L
As
Fish, rice,
vegetables
AA;HG;L
As
Fish, shellfish
AF;HG;LC
As
Baby food
AA;HG;HPLC
AA;ETA;L
As
Clam, oyster
CRM
AA;Tungsten
coil;L
As
Peanut butter
MS;ICP;IC
As
Nuts
MS;ICP;IC
As
As
Carrots, trout
Fish, crustaceans
MS;ICP;HPLC
MS;ICP;L
As
Chicken, fish,
rice
MS;ICP;HPLC
As
As
Chicken
White rice
MS;ICP;LC
MS;ES;L
As
Infant food and
formula
MS;ICP;L
As
Food
AA;HG;FI
As
Fish sauce
MS;ES;LC
Au
Foods
-;-;-
B
Diets
AE;ICP;L
Br
Cereals
MS;-;GC
Ca
Cheddar cheese
AA;-;L
Ca
AA;-;L
Ca
Diets, faeces,
sweat, urine
Diets
Cd
Tap water
AA;-;L
AE;ICP;L
AA;F;L
Cd
Sugar cane spirit
AA;ETA;L
Ref.
Al, Cd and Pb were determined with and without permanent
chemical modifiers such as Zr–Rh and Ir–Rh. The Al and Cd
results were better without the use of the modifiers
Al was determined following microwave digestion in a range of
Slovenian foodstuffs. Cooking sauerkraut and sour turnip in
Al cookware induced a significant rate of leaching
7 preservation methods for AsIII and AsV were discussed
7-day dietary intake of As, Hg and Se was studied for children
living on the North Sea island of Amrum, Germany. The Se
intakes were below recommended levels in a number of cases
As part of the ongoing As contaminated water crisis in Bangladesh,
100 samples of foods potentially affected by, for example, irrigation,
were analysed. Variable results within and between species were
recorded
An on-line decomposition method based on UV photolysis was used to
determine AB, AC, TMAO and TMI. The absolute LOD was 4–12 pg
As
H2O–CH3OH–CH3Cl and an enzymatic method were used to
extract As. AB was the major species present and there was no evidence
of degradation over shelf life or as a consequence of freeze-drying the
foods
Ir, Pd and Rh were evaluated as chemical modifiers in tungsten coilETAAS. Pd was not satisfactory, but Ir and Rh yielded 1.4 and 1.9-fold
increases in sensitivity, respectively. When applied to the actual
samples, Rh offered the superior performance
Following extraction with 2-butoxyethanol, As was speciated using
HG-IC-ICP-MS. AsIII, AsV, MMA and DMA were found in
commercial samples
Some of the difficulties in analysing nuts were discussed, e.g., hardness,
high lipid content, sample heterogeneity. Ultimately it was necessary to
determine As and its’ species in an oil fraction and the defatted sample
AsIII, AsV, DMA and AB were determined
Anion-exchange HPLC, employing a step elution, was used to speciate
AsIII, AsV, AB, DMA and MMA in trypsin extracts
The efficiency of H2O, H2O–CH3OH and H3PO4 at extracting As
species was evaluated. The best recoveries were obtained for 3
consecutive extractions using 1 : 1 CH3OH : H2O
DMA and AB were found to be present
As levels ranged from o0.025 to 0.271 mg g1 (wet-mass basis) in
samples from the USA
Reassuringly, total As levels in a range of samples were low, the highest
concentration being 320 ng g1 dry weight in cereal based products.
The samples were also speciated, and inorganic As, DMA and traces
of MMA reported
Sample solutions were carried in 2% H2SO4 and merged with KBH4.
A quartz tube furnace was used. The LOD was 0.2 mg l1 (in Chinese)
As was speciated in fish sauce and the starting fish raw material. AB
was the major species in the fish, DMA the major species in the sauce
Au and Pt intakes in 84 German children, aged 14–83 months, was
determined using the duplicate method. Pt levels were slightly higher in
subjects who ate exclusively retail products than those who ate a
mixture of retail and locally sourced products
A rather esoteric study reported the investigation of differences in B
intake between pupils in Polish pre-schools and boarding schools.
No significant differences were found
Samples of wheat, rye, oat, barley, maize and rice were analysed
(in German)
Changes in the insoluble: soluble Ca ratio and the impact on cheese
ripening were investigated
A study to estimate the Ca, Mg and P requirements of young
Japanese adults was reported
Daily dietary intake of Ca and Sr in Pakistan varied from
217 to 713 mg and 0.9 to 5.7 mg. The Ca intakes were inadequate
Cd as CdI42 was collected on naphthalene- methyltrioctylammonium
chloride adsorbent, eluted with HNO3 and determined by FAAS,
with an LOD of 0.6 ng ml1
See Al, ref. 212
212
240
231
226
227
204
191
94
183
192
190
193
190
229
257
185
320
230
243
250
321
322
284
244
196
212
357
Table 2
Element
Matrix
Technique;
atomisation;
presentation
Cd
Wine
AA;ETA;L
Cd
Tea
AA;ETA;L
Cd
Vegetables
AA;ETA;Sl
Cd
Honey
AA;ETA;L
Cd
Foods
AA;F;Sl
Cd
Bovine liver,
porcine kidney
and skimmed
milk powder
RMs
AA;ETA;L
Cd
Rice flour
MS;ICP;LA
Cd
Rice
MS;ICP;ID
Co
Drinking water
AA;ETA;L
Co
Honey
AA;F;FI
Co
Apple, pear,
mandarin orange
Beverages, foods
RIMS;-;L
Co
358
(continued )
AA;ETA;L
Cr
Alcoholic
beverages
AA;ETA;L
Cu
AA;ETA;L
Cu
Human milk,
infant formula
Biscuits
Cu
Foods
AA;F;L
AE;ICP;L
AA;F;L
Cu
Foods
AA;-;L
Cu
AA;-;L
Cu
Fe
Bovine liver
SRM, Tea leaf
SRM
Rice
Milk
MS;ICP;L
AA;ETA;L
Fe
Fe
Fe
Foods
Foods
Biscuits
AA;F;L
AA;-;L
AA;F;L
Hg
Milk
AF;CV;Sl
Ref.
Samples were microwave digested in HNO3 and Cd and Pb were
determined using Zeeman-effect ETAAS with NH4H2PO4 and
Mg(NO3)2 as chemical modifiers
Perhaps unsurprisingly the Cd and V content of infusions were
dependant on tea species and temperature of infusion
Ultrasonic slurry sampling ETAAS with a molybdenum tube atomiser
was used for the measurement of Cd in Bangladeshi vegetables
Honey was diluted in H2O and then H2O2, HNO3 and Triton X-100
added. The performance of Pd þ Mg and alternatively NH4H2PO4
as chemical modifier was compared
50–100 mg of lyophilised material was placed in a test tube, 5 ml HNO3
added, and the mixture sonicated. Following dilution to 10 ml
with H2O and then centrifugation, a 400 ml aliquot was taken for
‘‘beam injection flame furnace’’ AAS. The LODs for Cd and Pb
were 0.03 and 1.6 mg g1, respectively
An unusual digestion procedure (unlikely to appeal to every
organisations’ H and S officer) was described in which samples were
wrapped in paper, placed in a homemade quartz holder and then inside
the quartz vessels of a commercial microwave digestion apparatus.
NH4NO3 was added to the paper, the vessel pressurised using O2 to 15
bar and the sample irradiated at 1400 W for 20 s. The sample was
combusted in a few seconds and good recoveries reported
To construct the calibration line and estimate the LOD,
3 rice flour SRMs were used
Cd, Cu and Pb were certified in a candidate RM, for the Institute for
Reference Materials and Measurements using ID-ICP-MS.
The estimation of uncertainty was discussed in detail
Sorption on a conical minicolumn packed with activated carbon,
pH 9.5, yielded a 195-fold enrichment factor for a 10 ml sample
Co was complexed with 2-(5-bromo-2- pyridylazo)-5diethylaminophenol, retained on an anion exchange resin prior to
elution using C2H5OH
LODs of o5 pg were achieved
266
323
209
324
208
3
216
269
197
325
219
Samples were digested in a microwave oven using 6 ml
HNO3–1 ml H2O2
Cr and Sb were determined in a Brazilian spirit, Cachaca, using
ETAAS, with Ru as permanent modifier. Using matrix matched
standards the LODs were 2 and 43 pg for Cr and Sb, respectively
The effect of pH on enzymatic extraction procedures was investigated
294
Cu and Zn were determined in Croatian samples
326
Cu, Fe and Zn levels were determined in typical Nigerian foods, such as
yam pottage and fried plantain. Phytate was also determined,
by colorimetry, and phytate : Zn molar ratios calculated
Cu, Fe and Zn were determined in high intake Chilean foods following
digestion with HClO4–H2SO4–HNO3. Evidence of deficiency,
particularly of Zn, was reported
Aqueous sample was passed through a C18 membrane disc modified by
1-hydroxy-2-(prop-20 -enyl)-4-(prop-20 -enyloxy)-9,10-anthraquinone.
The retained Cu21 was then eluted using HNO3
See Cd, ref. 269
Samples were diluted in 10% v/v CFA-C, obviating the need for a
digestion step. Zeeman-effect background correction was employed
and Pd was used as chemical modifier during Se measurement
See Cu, ref. 246
See Cu, ref. 247
Different digestion procedures were compared for Fe and Zn
determination. A microwave procedure using HCl–HNO3, 3 þ 1, at
180 1C and 600 W yielded good results
Samples were sonicated for 10 min in a water bath in the presence of
8% (v/v) aqua regia–2% (v/v) antifoam A–1% (m/v) hydroxylamine
hydrochloride and then treated with 8 mM KBr and 1.6 mM KBrO3.
The LOD was 0.011 ng g1. See also, Various, ref. 207
246
241
211
247
8
269
210
246
247
194
223
Table 2
(continued )
Element
Matrix
Technique;
atomisation;
presentation
Hg
White wines
AA;CV;FI
Hg
Wine
AA;ETA;L
Hg
Rice
AF;HG;L
Hg
Hg
Foods
Seafood
AA;F;L
AF;-;GC
Hg
Fish
MS;-;GC
Hg
Food RMs
MS;ICP;ID
MS;ICP;HPLC
I
Salt
MS;ICP;ID
Mg
Diets, faeces,
sweat, urine
Human milk
AA;-;L
Mn
Mn
MS;ICP;SEC
AE;ICP;L
Ref.
Pre-treatment by ozonation allowed a major reduction in reagents
and faster analysis times. The LOD was 0.5 mg l1
Hg was preconcentrated from untreated wine by liquid: liquid
extraction, with APDC as complexing agent. The LOD was 0.2 mg l1
A microwave digestion method yielded an LOD of 0.005 ng ml1
(in Chinese)
See As, ref. 226
2 Hg speciation methods were described. In the first, Hgi and Hg
species were ethylated, in the second monoalkylated species
were extracted into organic solvent
Samples were microwave digested in TMAH, Cu21 added, derivatised
with sodium tetrapropylborate and extracted into n-heptane.
The LOD for methylmercury was 40 ng g1
As part of a study of contributions to uncertainty the mass fraction of
Hg was determined in 1 SRM by ID using MC-SF-ICP-MS whilst
the mass fraction of methylmercury in DORM-2 was determined
using HPLC-Q-ICP-MS
The applicability of the I catalysed reaction (Sandell–Kolthoff)
between Ce41 and As31 for the determination of I in salt samples
fortified with Fe and I has been studied. The catalytic method data
was compared with ICP-MS and no bias found
See Ca,284
236
215
327
226
224
127
129
328
284
Mn was speciated in various milk fractions. The species identified
included inorganic Mn and citrate complexes, together with
uncharacterised species
A survey of Canadian retail products suggested that soy and rice
beverages contained such high levels that they may pose a risk of
adverse neurological effects in infants
Samples were finely ground and introduced directly into the furnace
by means of solid autosampler system
Molybdenum(VI)–thiocyanate complex was collected on a mini-column
packed with polyurethane foam. The method yielded an LOD of
0.08 mg l1
The relationship between plasma Mo and dietary intake in humans was
investigated. The results demonstrated that, in contrast to most other
essential minerals, plasma Mo reflects low and high dietary
intakes within 14 days and may provide a useful indicator of dietary
intake
Results for the WDXRF method compared favourably with
those obtained using a standard Mo blue method
123
Mn
Rice beverages,
soy beverages,
infant formula
Vitamin tablets
AA;ETA;S
Mo
Water
AA;ETA;L
Mo
Diets, blood plasma
MS;ICP;L
P
WDXRF;-;S
AA;-;L
See Ca, ref. 284. P was determined spectrophotometrically
284
Pb
Genetically
modified and
non-genetically
modified foods
Diets, faeces,
sweat, urine
Tap water
AE;ICP;FI
201
Pb
Pb
Pb
Wine
Sugar cane spirit
Moonshine
AA;ETA;L
AA;ETA;L
AA;ETA;L
Pb
Water pipes
XRF;-;L, SIMS;;L
Pb
Oil seeds
AA;F;L
Pb
Smoked fish
AA;-;-
Pb
Foods
AA;ETA;L
A 300-fold preconcentration factor was achieved with cloud point
enrichment using polyethyleneglycolmono-p-nonylphenylether.
The ‘‘sensitivity’’ was quoted as of 0.077 mg l1
See Al,266
See Cd, ref. 212
A fascinating forensic case was reported. A high incidence of elevated
blood Pb in emergency clinic patients in Atlanta, USA, was found to
be linked to consumption of moonshine. A survey of 115 moonshine
samples seized between 1995–2001 showed 28.7% contained levels
above the limit designated potentially hazardous by the FDA
An array of techniques was used to characterise lead pipe corrosion
products in parts of the Scottish water supply. Secondary neutrals MS
showed relationships existed between C, Ca, Fe and P within the
bulk of the scale, as well as at the surface
A method based on micro-injection and derivative signal processing
for Pb and Zn determination was described (in Chinese)
A combination of traffic pollution and process contamination
resulted in Pb levels of Nigerian fish being 30 times greater than the
recommended safety limits
Dietary Pb intake was studied in groups of children and one group
of adults from the Ruhr and the German island of Amrum. Intakes
P
AA;-;L
242
214
329
130
222
266
212
235
330
331
233
234
359
Table 2
Element
360
(continued )
Matrix
Technique;
atomisation;
presentation
Pb
Pb
Foods
Fruit, vegetables,
herbs
AA;ETA,F;Sl
AE;ICP;L
Pb
Pd
Rice
Tap water
MS;ICP;L
AE;ICP;ETV
Pd
Mussels
AA;ETA;L
Pd
Lettuce
XRF;-;SEC
Pt
Water
AA;ETA;FI
Pt
Pt
Pt
Rh
Rh
Sb
AE;ICP;ETV
AA;ETA;L
-;-;AE;ICP;ETV
AA;ETA;L
AA;ETA;L
Sb
Tap water
Mussels
Foods
Tap water
Mussels
Alcoholic
beverages
Water
Se
Human milk
AF;HG;L
Se
Milk
AF;HG;L
Se
Drinking water
AA;ETA;FI
Se
AE;ICP;HG
Se
Infant formula,
human milk
Yeast
AA;F;L
Se
Se
Foods
Foods
AA;F;L
AF;HG;L
Se
Buckwheat,
pumpkin
AF;HG;L
Se
AF;-;HG
Se
Chicken livers,
dogfish liver
CRM, proteins
Vegetables
AF;-;HG
Se
Infant foods
AA;ETA;Sl
Se
AE;MIP;GC
Se
Garlic, mustard,
yeast
Garlic, onion
Se
Garlic
AA;ETA;L
MS;ICP;L
Se
Indian mustard,
lupin, sunflower
seeds
MS;ICP;HPLC
MS;ICP;L
MS;ICP;HPLC
were found to be low. Intake studies by the same group were also
reported in As, ref. 226 and Au, ref. 243
See Cd, ref. 208
Samples from gardens known to contain Pb-contaminated soil
were analysed. This resulted in the perhaps slightly optimistic
recommendation that ‘‘urban gardeners should test the lead levels in
their soils’’
See Cd, ref. 269
A novel method for determining Pd, Pt and Rh as their gaseous
DDC complexes, following ETV at 1100 1C, was described. The LODs
were 1.4, 5.4 and 0.8 ng ml1, respectively
A microwave digestion-ETAAS method for the determination of Pd,
Pt and Rh was described. The LODs were 90, 270 and 13 ng g1,
respectively
The binding of Pd to high Mr compounds was investigated using gel
permeation chromatography and preparative isotachophoresis.
At least 5 compounds were present
Pt was enriched, by a factor of 41.7, on silica gel functionalised using
1,5-bis(di-2-pyridyl)methylene thiocarbohydrazide. The silica column
was placed inside the autosampler arm. Using 60 s preconcentration
the LOD was 0.08 ng ml1
See Pd, ref. 138
See Pd, ref. 139
See Au, ref. 243
See Pd, ref. 138
See Pd, ref. 139
See Cr, ref. 211
Sb was determined as part of the ongoing study of Bangladeshi well
water contamination. The results did not support the hypothesis that
Sb is a significant confounder in the observed relationships between As
exposure through drinking water and potential health outcomes
Samples were digested using H2SO4–HNO3–H2O2. The LOD was
0.25 ng g1
Samples were treated by sonication with aqua regia and SeIV and TeIV
determined without pre-reduction. Total Se and Te were determined
after reduction by KBr and SeVI and TeVI obtained by difference
SeIV and SeVI were preconcentrated on a microcolumn placed in the
autosampler arm, then sequentially eluted using 0.1 M and then 4 M
HCl. Ir was used as permanent modifier
A study of Spanish retail samples found several formulae did not
reach the RDA for the first month of neonate life
A method yielding LOD and LOQ of 2.5 mg l1 and 5 mg l1 Se,
respectively, was reported
See As, ref. 226
The results of a survey of Croatian foods were described. The samples
were digested in HClO4–H2SO4–HNO3, 1 þ 1 þ 5
Foliar treatment with SeVI resulted in increases of Se content in
pumpkin fruit from 108 to 381 ng g1 and in buckwheat from
15 to 20 ng g1
A single tube method, based on HNO3–H2O2 digestion, yielded an
LOD of 0.2 ng g1 in the test solution
A very potent digestion mixture comprising H2SO4–HNO3–H2O2–
V2O5–HF ultimately yielded an LOD of 0.14 ng g1
Samples were suspended in 0.1% Triton X-100, 0.5 or 5% HNO3
and directly injected into the furnace. The LOD was 0.43 mg l1
Se was speciated using SPME-MIP-AES. Dimethylselenide,
diethylselenide and dimethyldiselenide were determined
Evidence was presented for the existence of Se ‘‘allins’’ (Se-alk(en)yl-Lcysteine selenoxides) in enriched samples
The 2 cited analytical methods were compared and found to offer good
agreement. Rh was used as the chemical modifier in the ETAAS
method and as internal standard in the ETAAS method
Se uptake and distribution was evaluated
Ref.
208
258
269
138
139
332
333
138
139
243
138
139
211
261
146
205
198
237
334
226
239
335
147
195
336
203
188
337
338
Table 2
(continued )
Element
Matrix
Technique;
atomisation;
presentation
Se
Yeast
MS;ICP;CZE
Se
Yeast
MS;ICP;LA
Se
Yeast
MS;-;ES
Se
Yeast
MS;-;ES
MALDI;-;MS
Se
Yeast
Se
Yeast-based
intervention agents
MS;ICP;HPLC
MS;ES;HPLC
MS;ICP;HPLC
Se
Mushrooms
Se
Green onions
Se
Edible plants
MS;ICP;HPLC
MS;ES;HPLC
MS;ICP;HPLC
MS;-;ES
MS;ICP;HPLC
Se
Animal muscle
MS;ICP;SEC
Se
Cod
MS;ICP;
HPLC,SEC
Sn
Tin packaging,
tomato juice
-;-;-
Sr
Diets
Sr
Wine
AA;-;L
AE;ICP;L
MS;ICP;L
Sr
Emmental
cheese
MS;ICP;L
Te
U
Milk
Foods
AF;HG;L
MS;ICP;L
V
Zn
Tea
Milk powder
AA;ETA;L
AA;F;FI
Zn
Zn
Zn
Zn
Foods
Oil seeds
Foods
Biscuits
Zn
Various (15)
Biscuits
Beverages
AA;F;L
AA;F;L
AA;-;L
AA;F;L
AE;ICP;L
AA;F;L
AA;-;L
Various (4)
Water
AA;ETA;L
Various (15)
Mineral water
XRF;SR;L
Various (7)
Milk, diary
products
AA;-;L
Various (5)
Milk
AF;HG;Sl
Ref.
More than 20 species were separated in cold H2O extracts of
dietary supplements. Absolute LODs were o250 fg
LA was used to study elements in a gel after gel electrophoresis.
A DRC was used to reduce interference from the Ar dimer
Recent method developments, including characterisation of the water
soluble protein fraction by MALDI-TOF-MS and ES
quadrupole-TOF tandem MS, were described
H2O soluble, cell-wall bound, and membrane-protein Se were
sequentially leached from the sample, followed by a further
fractionation by high-resolution SEC. SeMet in the H2O insoluble
fraction was found to be bound physically to cell wall constituents
Simulated gastric and intestinal digests were used to study Se speciation
187
Low Mr species were liberated from the samples by proteolytic
hydrolysis followed by separation by ion exchange LC and detection
by ICP-MS
SeMet was the principal species in selenised shiitake mushrooms
Se-cystine, methylselenocysteine, SeMet, g-glutamyl-Semethylselenocysteine and inorganic Se were identified
Sprouts of plants (10 families, 28 species including radish) were
cultivated in a high Se environment and then speciated. In addition
to Se-methylselenocysteine, SeMet, non-metabolized SeIV,
g-glutamyl-Se- methylselenocysteine and an unknown Se compound
were also detected in several high-selenium sprouts
These differences in Se distribution among 7 animal species were
discussed in relation to meat quality and nutritional value
An octopole reaction system was used to overcome Ar dimer
interference. Post-column ID was used to identify and quantify
species of which selenomethionine was the major one. 4 extraction
procedures were compared
An interesting study of gastrointestinal disorders following Sn
consumption suggested adverse effects were associated with the
form of the Sn rather than the concentration per se
See Ca, ref. 244
87
Sr : 86Sr were found to be a suitable marker in a study of the effect
of soil composition and vinification process on the ratio
The 87S : 86Sr ratios in cheese originating from different regions
(alpine, pre-alpine, Bretagne, Finland, Canada, Australia) accorded to
local geological properties. The extraction and digestion procedures
and interference correction regimes were detailed
See Se, ref. 205
The measured values of U were found to vary from 2.3 ng g1 to 11 ng
g1 dry weight and posed no health risk
See Cd, ref. 323
A FI system for the continuous ultrasound-assisted dissolution of solid
soluble samples, yielding a Zn LOD of 0.3 mg g1 was described
See Cu, ref. 246
See Pb,331
See Cu, ref. 247
See Cu, ref. 326
See Fe, ref. 194
A survey of 15 soft drinks produced in Pakistan found Al, Cd, Fe, Ni
and Pb above WHO recommendations
A study to identify preferred permanent modifiers was reported. For
Cd and Cr, Rh was selected, whereas Zr was preferred for Al and Pb
37 Brazilian retail samples were measured. Samples were placed on a
Perspex carrier, dried with an IR lamp and measured for 200 s
Ca, Cu, Fe, K, Mg, Na and Zn were determined in Argentinian
samples. The effect of processing, such as skimming, was discussed
(in Spanish)
Aqua regia was added to samples, 1 ml, which were then treated for
10 min in an ultrasound bath. Pre-reduction was then performed
35
202
339
172
173
186
184
238
340
189
270
244
265
218
205
245
323
179
246
331
247
326
194
263
213
220
253
207
361
Table 2
(continued )
Element
Various (5)
Beer
AE;ICP;LC
Various (5)
Milk, bovine liver,
kidney and serum
AE;ICP;L
Various (63)
Wine
MS;ICP;L
Various (13)
Wine
MS;ICP;L
Various (16)
Sparkling wine
Various (4)
Cow’s milk,
human milk,
baby foods
MS;ICP;L
AA;ETA;L
AA;HG;L
AA;F;L
Various (6)
Milk
Various
Human whey,
infant formula
Various (22)
Fish
-;-;-
Various (4)
AA;-;L
Various (10)
Margarine,
shortenings
Cereals
AA;F;L
342,343
Various (5)
Animal feed
AA;F;L
Various (7)
Eggs
AA;ETA;L
Various (8)
Lobster, milk
powder and
bovine liver RMs
Lobster and milk
powder RMs
AE;MIP;L
Various (4)
Various (14)
Honey
Bovine tissues
AE;ICP;L
AE;ICP;L
Various (9)
Pet food
AE;ICP;L
Various (7)
Bovine liver
AE;ICP;L
Various (10)
Seville oranges
MS;ICP;L
Various (6)
Mushrooms
MS;ICP;SEC
Various (10)
362
Matrix
Technique;
atomisation;
presentation
AE;ICP;L
MS;isotope
ratio;L
MS;ICP;SEC.
AE;MIP;Sl
with KBr (Se and Te) or KI–ascorbic acid (As and Sb). Bi could be
determined with or without pre-reduction. The samples were then
slurried with ‘‘antifoam A’’, treated with KBH4 and taken for HGAAS
Off-line preconcentration of Cd, Co, Cu, Ni and Zn was achieved using
the chelating resin ‘‘Metalfix Chelamine’’ and Dowex 50 W-X4.
Difficulties separating the analytes from the resin meant it was
necessary to digest the resin, rather than perform an elution step
Slight differences were observed between the industrial and nonindustrial regions of Turkey, but generally industrial activities and
seasonal changes had no significant effect on selected element
concentrations on cows and their milk (Cr, Cu, Fe, Mn, Zn)
German wines were microwave digested and In used as internal
standard in semiquant. mode. The study paid particular regard to the
influence of ingredients such as bentonite and yeast on element
composition
The same research group as in ref. 264 analysed 127 samples from
4 wine regions of Germany, using SF-ICP-MS and a simple 1 : 20
dilution of the sample. Classification based on decision tree was more
accurate than one using quadratic discriminant analysis
Pattern recognition techniques allowed Brut champagne and Brut cava
to be distinguished with 100% accuracy
3 sample digestion procedures using dry and wet ashing and microwave
oven were compared. Microwave methods offered the best
performance, except for the measurement of Fe in biscuits and
rice flour (Cu, Fe, Mn, Zn)
The geographical origin of 20 Italian milk samples was classified with
100% accuracy using multivariate chemometric methods
(Al, Ba, Cu, Fe, Mn, Zn)
The ICP-MS was fitted with an octopole reaction cell and speciation of
premature whey and premature infant formula conducted for essential
and toxic elements. Important differences in essential elements,
e.g., Cu, Fe and Zn were noted
The partial results were reported of a very comprehensive survey of
contaminants in Norwegian fish, of planned duration 1994–2010
The use of ultrasonic assisted acid extraction reduced the conventional
acid extraction time from 180 to 10 min
A pair of papers reported elemental levels in Pakistanian wheat
varieties (ref. 342) and maize hybrids (ref. 343)
A dynamic and automated ultrasound-assisted extractor was used for
Ca, Cu, Fe, Mg and Zn determination
The concentration of Cd and Pb in Nigerian eggs was higher than
reported levels from other parts of the world
Samples were mineralised using TMAH in a microwave oven
Slurries were prepared in 10% HNO3 containing 0.01% Triton X-100
and fed directly into the microwave cavity-torch assembly
(Ca, Cd, Cu, K, Mg, Mn, Na, P, Sr, Zn)
Cr, Fe, Mn and Ni were determined
The interactions between toxic elements (As, Cd, Hg and Pb) and
essential elements (Ca, Co, Cr, Cu, Fe, Mn, Mo, Ni, Se, Zn)
were investigated
Samples were prepared by microwave digestion. Due to the
heterogeneity of pet food premixes it was necessary to use large sample
sizes to avoid poor repeatability (Ca, Cr, Cu, Fe, Mg, Mn, Mo, Se, Zn)
Samples were partially digested using the vapour from HNO3–H2SO4
heated to 120 1C in a microwave oven (Al, Ca, Cu, Fe, Mg, Mn,
and Zn)
Al, Ba, Cd, Cr, Cu, Mn, Ni, Pb, V and Zn were determined in samples
from Seville and Palermo
0.05 M NaOH, 0.05 M HCl, and H2O at 60 1C were evaluated for
obtaining Mr distribution patterns for Ag, As, Cd, Hg, Pb and Sn
among different fractions
Ref.
199
252
264
274
275
341
277
251
260
181
180
268
14
15
344
347
225
4
345
346
Table 2
(continued )
Element
Matrix
Technique;
atomisation;
presentation
Various (5)
Rice flour
MS;ICP;ETV
Various (68)
MS;ICP;L
Various (8)
Animal and fish
tissues
Peas
Various (36)
Barley
MS;ICP;L
MS;IR;L
Various (15)
Yeast
MS;ICP;LA
Various (6)
Onion
XRF;-;L
Various
Beverages, foods
-;-;-
Various (5)
Food packaging
plastics
MS;ICP;L
MS;ICP;L
MS;ICP;SEC
Ref.
Ultrasonic slurry sampling-ETV-DRC-ICP-MS was used to determine
Cd, Cr, Cu, Hg and Pb at LODs of 0.4, 0.44, 1.7, 0.53 and 0.60 ng g1,
respectively. Ascorbic acid was used as chemical modifier
SF-ICP-MS, following microwave-assisted digestion using HNO3,
was applied to the analysis of muscle, liver, kidney, lung and brain
The effect of cooking on concentrations of Co, Cu, Fe, Mn, Mo,
Ni, P and Zn was studied. Soluble high molecular weight species,
present in the original pea, were completely removed by boiling
The study examined the possibility of generating a unique elemental
fingerprint of individual barley genotypes irrespective of soils
fertility and agricultural practice
In addition to the analysis of Se described in ref. 35, the LOD,
range and linearity of other elements were calculated
Analyte elements were extracted by ultrasonic agitation in acid. The
results were compared with dry and wet ashing. Differences in element
concentrations were found between 2 cultivars (Ca, Cu, Fe, K, Mn, Zn)
A review of developments in the atomic spectrometric determination
of beverages and foods
Samples were digested in HNO3–H2O2 using a high pressure
microwave system (As, Cd, Cr, Pb, Sb)
217
region of viniculture. This approach has been applied to
Swiss,273 German274 and other wines.275,276 More recently it
has emerged that Sr isotopic ratios may serve this purpose and
some preliminary work has been reported for wines from the
Portuguese district of Douro265 and for Emmental-type cheeses
from Australia, Canada, Finland and France.218 Other workers have applied preliminary measurements of trace elements to
identify the origin of cow milk in Italy277 and Danish barley.256
Analyses of foods and beverages are set down in Table 2.
4 Conclusions
Over the years, Atomic Spectrometry Updates has been chronicling advances in the application of ICP-MS to the analysis of
clinical and biological samples, foods and beverages. This year, it
is evident we are moving into a new phase. Previous Updates
have commented on the few papers appearing that used
dynamic reaction cells or octopole cells with quadrupole
ICP-mass spectrometers in the clinical field. This year, there
are many more and it is clear that these spectrometers are now
standard in many laboratories. Other laboratories have standardised on sector-field ICP-mass spectrometers, once just a
research curiosity. The reason for this advance is clear. Isobaric
interferences have been a difficult problem to solve for researchers trying to apply ICP-MS to the determination of
certain elements in the clinical field. Both sector-field ICPMS and dynamic reaction or octopole cells in quadrupole ICPMS drastically reduce these interferences, leading to improved
accuracy. As Sturup commented,22 these and other advances
have resulted in ICP-MS replacing the more complicated
TIMS technique for isotope studies in nutritional research.
An interesting application of the DRC was to determine P and
S in cell culture digests as PO1 and SO1 through the addition
of O2 to the reaction cell.133
Aleixo et al.208 showed that there are still opportunities for
innovation involving FAAS with the beam injection system
permitting useful improvements in the LODs for Cd and Pb
in slurried powdered samples.
In recent years, the extension of in vivo XRF determination to
elements other than Pb has been noted. In this review, the
feasability of measurement of Ag and As in skin has been
assessed49,50 and there has been some interesting development
31
272
256
35
178
1
271
in the potentially useful assesment of prostate cancer by in vivo
determination of Zn in the prostate.51,52
The pollution of groundwater in West Bengal with As has been
a disaster to the people living in the affected areas. Recent
studies have shown, through hair and nail analysis, that nail is
a good biomarker for As75 and has indicated that other
elements, such as Mn, Ni and Pb, may have been involved.
A suggestion that the clinical problems were related to Sb
exposure has been disproved, as levels of Sb in the water were
insignificant.261 Speciation of the As in hair and nails indicates
that AsIII is the main species involved.75 Abnormally high As
concentrations found in fossil skeletons of dinosaur species led
Zhou et al.98 to suggest that As toxicity could have contributed
to the extinction of dinosaurs in the Chinese Province of
Sichuan. Contrast this to the current interest in the use of As
to treat carcinomas.96,97
Speciation of As and Se remains a topical subject, increasing
our knowledge but also showing the increased complexity of
the situation. Ten species have been found in human urine after
ingestion of selenised yeast,149,150 but only three have been
identified so far. The bioavailability of SeMet was shown to be
rather more complex than originally appeared when a study
using selenised yeast in cancer prevention programmes demonstrated that SeMet in this form causes greater increases in
serum Se than does simple synthetic SeMet. Arsenobetaine, the
major form of As in fish, was once thought to stable and nontoxic. Kato et al.230 showed that, once fish is made into a sauce,
most of the AsB has been converted to MMA. This study
confirms earlier studies indicating that AsB can be broken
down to more toxic As species. Meanwhile, Rattaanachongkiat
et al.193 found that where there is sufficient inorganic As in the
water not all will be metabolised to AB and the fish can then
present a significant health risk.
The story of Cd contamination of rice in Japan, leading to
Itai-Itai disease, is very well known. Now, more than 30 years
later, it is evident that remediation work has been successful
but still the concentrations of Cd in Japanese rice are greater
than elsewhere and the costs in terms of human tragedy are
incalculable. Should there ever be contamination of food from
the packaging, further disasters may emerge. What might be
thought to be a potential problem, with migration of Sn from
cans, appears to be of little concern as no adverse effects could
be demonstrated by the Sn species thus formed.270
363
(continued )
Appendix
Abbreviations used in this update
Abbreviations used in this update
AA
AAS
AB
AC
AES
AFS
AMS
APDC
BCR
CE
CRM
CSF
CSV
CV-AAS
CV-AFS
CZE
DDC
DIN
DMA
DMF
DNA
DRC
DTPA
EDTA
EDXRF
EI-MS
EPMA
EPR
ES-MS
ES-Q-TOFMS
ETA
ETAAS
ETV
FAAS
FAES
FAO
FDA
FI
GC-MS
HGAAS
HGAFS
HPLC
HR-ICP-MS
IAEA
IBMK
ICP
ICP-MS
ID
ISO
LA-ICP-MS
LC-ICP-MS
LOD
LOQ
m0
MALDI
MC
MIP
MMA
Mr
MRI
MS
NAA
NCT
NIES
364
Atomic absorption
Atomic absorption spectrometry
Arsenobetaine
Arsenocholine
Atomic emission spectrometry
Atomic fluorescence spectrometry
Accelerator mass spectrometry
Ammonium pyrrolidinedithiocarbamate
Bureau Communité de Référence
Capillary electrophoresis
Certified reference material
Cerebrospinal fluid
Cathodic stripping voltametry
Cold vapour AAS
Cold vapour AFS
Capillary zone electrophoresis
Diethyldithiocarbamate
Direct injection nebuliser
Dimethylarsinic acid
NN-dimethylformamide
Deoxyribose nucleic acid
Dynamic reaction cell
Diethylenetriaminepentaacetic acid
Ethylenediaminetetraacetic acid
Energy dispersive XRF
Electron impact-MS
Electron probe microanalysis
Electron paramagnetic resonance
Electrospray MS
Electrospray-quadrupole
TOF-MS
Electrothermal atomisation
Electrothermal atomisation AAS
Electrothermal vaporisation
Flame AAS
Flame AES
Food and Agriculture Organisation
Food and Drug Adminstration
Flow injection
Gas chromatography-MS
Hydride generation AAS
Hydride generation AFS
High performance liquid chromatography
High resolution ICP-MS
International Atomic Energy Authority
Isobutyl methyl ketone
Inductively coupled plasma
Inductively coupled plasma-mass spectrometry
Isotope dilution
International Standards Organisation
Laser ablation ICP-MS
Liquid chromatography ICP-MS
Limit of detection
Limit of quantitation
Characteristic mass
Matrix-assisted laser desorption ionization
Multiple collector
Microwave induced plasma
Monomethylarsonic acid
Relative molecular mass
Magnetic resonance imaging
Mass spectrometry
Neutron activation analysis
Neutron capture therapy
National Institute for Environmental Studies
NIST
NMR
OES
PAGE
PIXE
PTFE
RDA
RIMS
RM
RSD
SDS
SEC
SeCys
SeMet
SF-ICP-MS
SIMS
SPME
SRM
SRXRF
TCA
THGA
TIMS
TMA
TMAH
TMAO
TMI
TOF-ICP-MS
TXRF
WDXRF
WHO
XANES
XRF
National Institute of Standards Technology
Nuclear magnetic resonance
Optical emission spectrometry
Polyacrylamide gel electrophoresis
Particle-induced X-ray emission
Poly(tetrafluorethylene)
Recommended dietary allowance
Resonance ionisation-MS
Reference material
Relative standard deviation
Sodium dodecylsulfate
Size exclusion chromatography
Selenocysteine
Selenomethionine
Sector field ICP-MS
Secondary ion MS
Solid phase microextraction
Standard reference material
Synchrotron radiation XRF
Trichloroacetic acid
Transversely heated graphite atomiser
Thermal ionisation MS
Trimethylarsine
Tetramethylammonium hydroxide
Trimethylarsine oxide
Tetramethylarsonium ion
Time-of-flight ICP-MS
Total reflection XRF
Wavelength dispersive XRF
World Health Organisation
X-ray absorption near-edge structure
X-ray fluorescence
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Atomic spectrometry update. Clinical and biological materials, foods and beverages

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