Odor search poster

 Odor Search: Matching GC/MS Library search results and odor active compounds Philippe Mottay1; Robert Stoop2; Peter Picher2; Urs Hofstetter2 1
Brechbuehler, Inc., Houston, TX; 2Brechbuehler AG, Schlieren, Switzerland Introduction As GC and GC/MS are not always sufficient for olfactory analysis, chemists turn to GC‐O for the detection of low level odor active compounds. GC‐O is a powerful but time consuming technique. Odor search is a tool designed to facilitate the transition between GC/MS and GC‐O experiment. By comparing the library search results to a database of odor active compounds we are able to predict the area of interest to the GC‐O panelist. In addition, the software might help solve the problem without having to perform GC‐O. An example on the analysis of soft drink odor profile is described. The problem Food, beverage and other consumers’ products can lead to complex chromatograms. A challenge facing the analytical chemists is the identification of odor active compounds. Today’s GC/MS can easily identify compounds at low level. However library searches do not yield any odor information. A link between the library and an odor database is needed. Odor search is such link. The Solution Odor search takes the results from a library search performed from a GC/MS run. It compares each GC/MS library match to the internal odor database and list all common compounds found both in the chromatogram and the odor database. Thermo’s Xcalibur has the capability of auto processing the data file, performing integration of the chromatograms, and library search of the peaks found. It produces a results file (filename.rst) containing the information on the data processed (peak data, library matches, etc…) Odor search reads the results file and compare each library match based on the CAS number. It displays the chromatogram and raw spectrum as well as the library spectrum. Once a search is completed, it is possible to search for specific odor in the results. Our odor library consists of 5889 compounds (some duplicates) created from data gathered on the internet. Since fragrance and flavor companies usually created their own libraries, it is possible to import the data into Odor search. While the number of field is unlimited there are some restrictions to the entries. The software needs at least the compound name, the CAS number and the associated odor. Additionally, specific information includes the structure file (jpeg, bitmap or gif) and retention indexes. The remaining data such as molecular weight, formula, boiling point, (etc…) is treated as custom information. 3845 FM1960 RD W # 275 ‐ Houston, TX 77068 Tel: 281 880‐6963 – [email protected] Comparing Chromatograms Odor Search also allows comparison of chromatogram. A chromatogram database can be created from the result file. For example several acceptable samples and some bad samples can be entered. The Current chromatogram can searched against this library of chromatogram. The common peaks between the best match and the sample can then be removed from the list of odor active compounds leaving the compounds of interest. Another application is to enter a database of essential oils. The sample can then be compared to the chromatogram database and if it contains an essential oil it will show as a match. Analysis of an energy drink An energy drink was analyzed using by GC/MS using ITEX headspace technique. The GC/MS was a Trace DSQII (Thermo Electron). Conditions: 40°C – 1min to 100°C @5°C/min to 250°C@10°C/min hold 5min Injector: 250°C Split (25:1) MS: Scan1: 10‐150AMU in 0.2s Scan2: 34‐365AMU in 0.16s Sampling by ITEX 3845 FM1960 RD W # 275 ‐ Houston, TX 77068 Tel: 281 880‐6963 – [email protected] 3845 FM1960 RD W # 275 ‐ Houston, TX 77068 Tel: 281 880‐6963 – [email protected] Results from Odor search 3845 FM1960 RD W # 275 ‐ Houston, TX 77068 Tel: 281 880‐6963 – [email protected] GC‐O Experiment Volatile part of the chromatogram RT: 0.97 - 7.16
NL:
2.85E9
TIC F: + c Full
ms
[35.00450.00] MS
Red_Bull_141
107_04
3.90
44
42
40
1.48
38
36
3.09
34
32
30
Relative Abundance
28
26
24
22
6.71
20
18
16
14
12
10
8
6
1.81
1.99
6.03
4
2
1.70
1.14 1.40
2.14
2.44
3.30 3.50 3.75
4.09 4.16
5.65
5.13
4.56
4.78 4.88
5.30 5.43
5.77
6.33 6.43
6.89
6.5
7.0
0
1.0
1.5
2.0
2.5
3.0
3.5
4.0
Time (min)
4.5
5.0
5.5
6.0
3845 FM1960 RD W # 275 ‐ Houston, TX 77068 Tel: 281 880‐6963 – [email protected] Middle section of the chromatogram RT: 6.79 - 14.01
NL:
5.08E 7
TIC F: + c Full
ms
[35.00450.00] MS
Red_B ull_141
107_04
100
95
90
85
80
75
8.55
Relative Abundance
70
65
11.11
60
13.80
55
13.35
50
6.89
7.46
45
6.98
40
7.06
7.50
7.52
11.92
7.87
12.41
7.93 8.00
8.32
35
8.65
8.81 9.10
9.23
30
9.41 9.68
9.98
10.03 10.29
10.47
13.14
10.76
25
7.0
7.5
8.0
8.5
9.0
9.5
10.0
10.5
Time (min)
11.0
11.23 11.44
11.5
12.03
12.0
12.49
12.5
13.44
13.10
13.0
13.5
14.0
High temperature section 3845 FM1960 RD W # 275 ‐ Houston, TX 77068 Tel: 281 880‐6963 – [email protected] Reporting The software reports either a single peak or a summary or all peaks identified
3845 FM1960 RD W # 275 ‐ Houston, TX 77068 Tel: 281 880‐6963 – [email protected] Figure 6: Summary report (first page shown)
Figure7: Single peak report (1st match shown only) Conclusion Odor Search is a powerful tool for determining odor active compounds. For some of the samples Odor Search was sufficient to troubleshoot taste issue. For other samples, the combination of GC/MS, Odor Search and GC‐O helped troubleshooting the samples. The Chromatogram search function compares the sample to stored chromatograms. This can be used for determining essential oils contained in the samples. Odor Search is only available with Thermo’s Xcalibur. We are looking in ways to expand the scope of this software. Contact information: Philippe Mottay Brechbuehler, Inc. 3845 FM1960 RD W # 275 Houston, TX 77068 Tel: 281 880‐6963 / 281 541‐4112 E‐mail: [email protected] 3845 FM1960 RD W # 275 ‐ Houston, TX 77068 Tel: 281 880‐6963 – [email protected]