Studies On Determination Of Chemical Constituents In Ginkgo Biloba By Gas Chromatography/Mass Spectrometry With On-Line Pyrolytic Methylation

Ginkgo biloba leaves extracts(Egb) are mainly used for the improvement of the blood circulation,both peripherally and centrally.The constituents including fatty acids,alkylphenols and phenols in Ginkgo biloba also play an important role in the areas of chemical,pharmaceutical and food industry.In this thesis,the method to determine fatty acids,alkylphenols and phenols of Ginkgo biloba was developed on the basis of on-line pyrolytic methylation-gas chromatography/mass spectrometry (GC/MS).The multi-constituents of fermentation broth of Ginkgo biloba was also analyzed by this method.At first,on-line pyrolytic methylation-GC/MS using a vertical microfurnace pyrolyzer was applied to analysis of multi-chemical constituents for G biloba leaves simultaneously and directly.Pyrolytic methylation of G biloba leaves at 300℃in the presence of tetramethylammonium hydroxide(TMAH),allowed quantitative analysis of 6 kinds of fatty acid,9 kinds of alkylphenols and 5 kinds of phenols as their corresponding methyl derivatives,with the relative standard deviations(RSDs) less than 5.9%(n=3).Then,on the relative peak intensity on the chromatogram obtained by this method,the chemical composition for G biloba leaf samples collected from different growing place and different season were estimated and compared.As a result, the chemical composition for different season samples showed more variation than those for different growing place samples.Then,the method of on-line pyrolytic methylation-GC/MS was applied to determine fatty acids,alkylphenols and phenols in exocarp,sarcoderm,endopleura and seed of Ginkgo biloba samples collected from august to november.In exocarp part 23 compounds were identified and the constituents were estimated as 57%～73%, 22%～38%and 4.5%～5.8%for alkylphenols,phenols and fatty acids,respectively. 22 compounds were identified in endopleura part,the content of the constituents were 62%～73%,25%～36%and 8%～13%for phenols,fatty acids and alkylphenol, respectively.And 9 compounds are identified in seed,the constituents were estimated as about 90%,8.6%～10%and 0.5%～0.8%for fatty acids,phenols and alkylphenol, respectively.Although the concentration of the compounds varies as the season changes,the chemical composition of the exocarp consisted mostly of alkylphenols (57%～73%) and that of the seed consisted mostly of fatty acids(90%).Furthermore,the method of on-line pyrolytic methylation-GC/MS was applied to determine the multi-chemical constituents of fermentation broth from Ginkgo biloba. 15 compounds are identified,including 9 kinds of fatty acid,one kind of alkylphenol and 5 kinds of phenols with the relative standard deviations(RSDs) less than 5.2% (n=3).It shows good reproducibility.The obtainted results show that the developed method is rapid,convenience and highly sensitive for the chemical composition analysis of multi-constituents for Ginkgo biloba.