Rapid Identification on Chemical Constituents in Volatile Oil of Saposhnikovia divaricate by GC£­Q/TOF MS

KeyWord:Saposhnikovia divaricate  component identification  gas chromatography£­quadrupole time-of-flight mass spectrometry£¨GC£­Q/TOF MS£©  variable energy ionization source  MS2

Abstract:

      In this paper£¬gas chromatography£­quadrupole time-of-flight mass spectrometry£¨GC£­Q/TOF MS£© was used to identify the chemical constituents in the volatile oil of Saposhnikovia divaricate£®Firstly£¬the samples were analyzed under standard EI ionization source mode£¬and the qualitative software was used for data deconvolution and NIST library comparison£®82 compounds were identified£¬including hydrocarbons£¬aldehydes£¬ketones£¬alcohols£¬organic acids and esters£®Furthermore£¬the low energy ionization source£¨lower energy£©mode of GC£­Q/TOF MS was utilized to determine the molecular ion peaks of the unknown compounds£®And then£¬the secondary mass spectra of unknown compounds were acquired to obtain the fragment ion information so as to infer the molecular formula£¬and further identify the chemical structures combined with Chemspider database£®As a result£¬two compounds outside the NIST library were identified by this new method as£¨5E£¬7E£¬11S£©-5£¬11-dimethyl-5£¬7-tridecadien-1-alkyn-4-ol and£¨6S£¬7E£¬9E£©-7£¬9-heptadecadiene-11£¬13-diyn-6-ol£¬and three components in the NIST library were identified as 2£¬4-decadienal£¬tetradecanoic acid and methyl ester hexadecanoic acid£¬which were consistent with the automatic matching results and verified the feasibility of the proposed method. To sum up£¬a total of 84 chemical components were identified from the volatile oil of Saposhnikovia divaricate. This research not only enrich the application of GC£­Q/TOF MS in identification on volatile oil of Saposhnikovia divaricate£¬but also provide a new idea for the rapid and comprehensive identification of other chemicals. In particular£¬the combination of lower energy and MS2 mode of GC£­Q/TOF MS could be applied to the accurate and rapid identification of compounds not included in the NIST library.