TargetView application: Tobacco
Aroma profiling of tobacco using an integrated headspace-thermal desorption (HS-TD)-GC/MS system and TargetView software
Introduction
To analyse the aroma profile of tobacco samples an integrated HS-TD-GC/MS system was used. Multiple headspace extractions can be taken from a single vial using HS coupled with TD to provide significanlty increased sensitivity compared with static HS methods. This is important because most characteristic aroma components in tobacco exist at trace level.
GC/MS analysis of the headspace vapours produces a complex TIC (total ion chromatogram) from which, and using TargetView software, the tobacco aroma compounds can be located and identified. The approach, usng TargetView, ensures that high-quality, accurate and reliable identification of the tobacco aroma compounds is made.
Experimental
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Results
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- HS5-TD™ was coupled with a UNITY™ thermal desorpber (both Markes International Ltd.)
- Two samples were used for comparative purposes; an indian tobacco and tobacco from a UK ready-rolled cigarette.
- 0.5 g of each tobacco was weighed into individual 20 mL glass headspace vials and sealed with blue silicone PTFE septa
- See application note ANTV13 for full analytical conditions
- A TargetView library of tobacco flavour compounds was prepared and both samples analysed for their content.
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Enlarged TIC profiles for Indian (black) and UK tobacco (blue)
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| The VOC composition after 10 minutes is signifcantly higher for the Indian sample than the UK tobacco, with much greater concentrations of linolool (15.3 mins), citronellol (16.58 mins), linalyl acetate (16.92 mins) and nicotine (18.43 mins), for example. |
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Table of basic tobacco flavour compounds (left) & TargetView user interface with the target compound pyridine identified and highlighted (above)
Observations
Post-run TargetView reports for the analysis of basic compou8nds within the Indian and UK tobacco samples are shown below. A minimum match coefficient value of 0.75 enabled target compound identification with a high degree of confidence.
The TargetView report also provides information about the concentrations of target compounds identified; in this application example the compounds methyl pyrazine, dimethyl pyridine and nicotine, which are present in both samples, are at much higher levels in the Indian tobacco sample. Additionally, the Indian tobacco sample contains pyridine.
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Post-analysis report for basic compounds within Indian tobacco
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Post-analysis report for basic compounds within UK tobacco
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Conclusion
TargetView has the ability to cross-search the deconvoluted spectra of both target and unknown compounds against a NIST database (e.g. mainlib).
Furthermore, the calculation procedure used to calculate the match coeffcient is the same as the NIST search engine, making the numbers directly comparable
Results obtained by cross-searching the pyridine sample spectrum against the NIST database (right)
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TargetView is a powerful data-mining software, capable of identifying target analytes within complex mixtures. The
main processing algorithms of dynamic background compensation, spectral deconvolution and chemometric PCA
operate synergistically to enhance the identifcation process far beyond that possible when using conventional libraries and search techniques.
Unlike many software programs for compound identifcation, the user requires no knowledge of deconvolution or chemometrics; this is all addressed by the software.
From file selection to automated report generation use of TargetView is simple, making this software a very user-friendly platform whilst producing high quality results.
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