| This Study explored the technology and method of flue-cured tobacco GC/MS fingerprint withtobacco leaves from YunNan, Guizhou, Hubei, Shandong and Fujian as materials. Flue-curedtobacco GC/MS fingerprint of Nanping was built as an example, while it was presented by experiments.The construction method and validation of this flue-cured tobacco GC/MS fingerprint contained: In thispaper, the best treatment methods and equipment conditions was built by taking trials, such as structureand testing of the the GC/MS fingerprintex, analytic comparison of different extraction methods andextraction equipment of flue-cured tobacco. Standard fingerprint of the scent, strength, quality gradeswas constructed by sensory taste. Similarity evaluation system of the Nanping flue-cured tobaccofingerprint was built by similarities to samples and fingerprint and the threshold of the standardfingerprint. GC/MS Fingerprint of Tobacco has been verified, while the software of the similarityevaluation system of fingerprint has been werified too. It is showed that the technology and method offlue-cured tobacco GC/MS fingerprint were able to provide a new theoretical ground of flue-curedtobacco quality control and break new ground. The main results were as follows:1. The methods study on GC/MS fingerprint of flue-cured tobacco.Tobacco GC/MS fingerprint was constructed mainly including experiments as follows, methodoptimization and selecting of tobacco processing methods, extraction agents, chromatographic column,internal standard, starting temperature, injector temperature, interface temperature and warmingprogram. Final the optimization processing method of flue-cured tobacco was determined as follows,flue-cured tobacco extracted3hours by simultaneous distillation and the internal standard wasdecyl alcohol. The chromatography conditions was used by HP-5MS chromatographic column, injectortemperature:260℃, the interface temperature:280℃, temperature program:60℃(2min) with2℃/min rose to200℃(5min) again with2℃/min rose to220℃(0min) again with10℃/min rose to260℃(15min), flow rate:1.2ml/min.The methodology which can meet the request of fingerprint wasinvestigated included repeatability, stability and precision. It also built the method of how to choosecharacteristic fingerprint peak and the method of how to construct standard fingerprint.2. The similarity evaluation of GC/MS fingerprint of flue-cured tobacco.According to the results of sensory taste of flue-cured tobacco in Nanping, flue-cured tobaccosamples were divided into three flavor types, four impact types(strength of bigger, medium, medium-,medium+),and three quality classes(better, medium, medium+). Samples of different categories weredetected by GC-MS, and characteristic peaks were chosen by multiple comparison. The number ofcharacteristic peaks about odor type, strength and quality class were56,76and66. Finally, according tothe method of the median to built standard fingerprint of each type. Calculating the similarity of eachsamples with the standard fingerprint by correlation coefficient, Angle cosine, Euclidean distance anddegree similarity. Taking the the smallest of similarity value as the threshold. Principal componentanalysis and projection map were used to analysed the samples from Nanping. The2d distribution projection map could make it graphic and vivid to reflect every category of flue-cured tobacco. It wasintuitive explanation about this system.3. Verification of the Similar evaluation of the GC/MS fingerprint softwareIn order to validate accuracy of the quality control system of flue-cured tobacco for different flavortypes, unknown samples was chosen to take experiments. To check the effect of the method, test resultsfrom the system was compared with results by sensory taste.40unknown samples of tobacco leavesfrom nanping and other unknown samples from Yunnan, Hubei and Guizhou(each place had6samples)were chosen to verify the system. The result shows that the accuracy rate (odor type, strength andquality class) of this system was about more than70%. Verification results of the unknown samplesfrom other provinces also had high consistency. Unknown samples and each system were also analysedby the projection map of main component and cluster analysis, and the results showed that the effectwas better.4. Software of the GC/MS fingerprintIn order to better use this system for control quality of flue-cured tobacco, software was built."Traditional Chinese medicine chromatographic fingerprint similarity evaluation system A version "issued by Chinese pharmacopoeia committee was found can meet the requirements very well. Similaritywas analyzed with odor type as an example in this software, and the results were accurate too. Toconsider the problems in this software, more attention should be paid in the course of usage... |
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