Application Of Headspace Solid Phase Microextraction Coupled With Comprehensive Two-dimensional Gas Chromatography Mass Spectrometry In Identification Of Medicine And Food Homologous Products Region

With people's pursuit of dietary therapy for health,more and more medicinal food was favored.The quality of medicinal foods is influenced by the region,and the quality of goods on the market varies.At present,the market demand for homologous foods was increasing.Traders often falsified the origin,adulterate the ingredients,and maed the efficacy components unclear in order to obtain greater benefits.To regulate the market of homologous foods and protect the rights and interests of consumers,it was necessary to establish scientific origin identification techniques.The volatile compounds of the subjects were detected by headspace-solid phase microextraction with comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry.(HS/SPME-GC×GC-TOFMS)combining chemometric methods.The method could effectively identify Ningxia wolfberry and Xinhui Chenpi,which both provided a reference basis for the quality evaluation on identification of wolfberry and Chenpi,and a new idea and method for the quality evaluation of other medicinal foods of the same origin.The HS/SPME-GC×GC-TOFMS system consisted of a multifunctional autosampler,gas chromatography,solid-state modulator and the time-of-flight mass spectrometry,which was selfdeveloped by my team.The performance test results of the system showed that: the detection limit test of 1 pg/?L OFN,M/z=272 signal-to-noise ratio >100:1.The ion resolution of tuning liquid PFTBA with M/z=502 reached 1120;the maximum deviation of mass axis accuracy was 0.04 amu,which was less than the basic regulation of 0.1amu;the repeatability of quantification RSD=4.0%,and the dynamic test range reaches 105,Th can meet the experimental requirements.The conclusions of this study were as follows.(1)The optimal conditions for headspace solid-phase microextraction coupled with comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry for the detection of volatile substances of Lycium barbarum were as follows: the column system was a one-dimensional column DB-Innowax(30 m×0.25 mm×0.25 ?m)with a two-dimensional column DB-17(1.3 m×0.18 mm×0.18 ?m),the extraction head type was 50/30 ?m PDMS/DVB/CAR,the extraction temperature was 70 ?,and the extraction time was 40 min,the sample showed the best peak results for the volatile components and the largest number of compounds.(2)In this study,HS/SPME-GC×GC-TOFMS analysis was performed on samples of Lycium barbarum from different origins.There were 328 substances with positive and negative matches over 800 in the volatile components of Ningxia wolfberry,which enriched the information of wolfberry volatile components.Principal component analysis(PCA)and cluster analysis(HCA)were used to achieve the purpose of distinguishing the five origins.Further partial least squaresdiscriminant analysis(OPLS-DA)was used to obtain 15 potentially differential compounds between Ningxia wolfberry and other wolfberries,of which 10 compounds,only orcinol,(R)-3,5,5-Trimethylcyclohex-3-en-1-ol and Ethyl N-(o-anisyl)formimidate were detected only in Ningxia wolfberry.The experimental results indicated that these 10 compounds were potential markers of Ningxia wolfberry.(3)In this study,HS/SPME-GC×GC-TOFMS analysis was also performed on Chenopodium samples from different origins.About 500 compounds were detected in a single sample,and 102 common components in Xinhui peel were obtained by screening.These common compounds were mainly terpenoids and alcohols,which together formed the unique aroma characteristics and pharmacological effects of Xinhui Chenpi.Combined with principal component analysis(PCA)and orthogonal partial least squares(OPLS-DA)to achieve the purpose of identifying Xinhui peel with other peels,we obtained 13 potential differential compounds between Xinhui peel and other peels.3-Methyl-6-(1-methylethylidene)-2-cyclohexen-1-one was only detected in Xinhui peel,which indicated that menthone was a potential marker to Xinhui peel.HS/SPME-GC×GC-TOFMS combined with chemometric method can effectively identify Ningxia wolfberry and Xinhui Chenpi,which can provide a reference basis for the quality evaluation and identification of wolfberry and Chenpi,and provide new ideas and new methods for the quality evaluation of other medicinal food products.