Identification Of Phytochemicals From Three Plants By HPLC-ESI-MS~n

High performance liquid chromatography combined with multi-stage electrospray tandem mass spectrometry (HPLC-ESI-MSn) hybridizes the high separation ability of HPLC along with the fast detection specificity of MS. HPLC-ESI-MSn not only possesses high sensitivity, short analysis time, but also can be used to analysis with quite low sample amount. It has been widely applied as a powerful and popular tool in various medicinal plants analysis. In this dissertation, a liquid chromatography/multi-stage electrospray tandem mass spectrometry method was developed to identify the phytochemicals of three plant, Botrychium ternatum, the flowering head of Chrysanthemum morifolium Ramat and the fruit of Citrus medica L. var. sarcodactylis Swingle. The detailed specifications were divided into three parts.Part 1 A quick structure identification of flavonol glycosides from Botrychium ternatum, a traditional Chinese herb, was developed by high performance liquid chromatography equipped with multi-stage electrospray ionization mass spectrometry. The flavonol glycosides in the extracts of Botrychium ternatum were analyzed in three steps. First, HPLC gradient elution was used to characterize flavonol glycosides extracted from Botrychium ternatum by n-butanol and acetic ether according to the various polarities, and 32 peaks obtained were further diagnosed by tandem mass spectrometry. Second, the diagnostic fragmentions of aglycone moiety in MS/MS spectra indicated authentic evidences for the skeletons of flavonols. Third, in full scan mass spectra, different saccharide losses, unique cleavage sequence and positive or negative product ions were observed for flavonol glycosides with different sugar moiety and substitution positions. As a result, there were 27 flavonol glycosides identified by fragmentation patterns in the extracts of Botrychium ternatum.Part 2 A microwave-assisted extraction approach based on ionic liquids with different chain lengths was successfully applied in extracting ten flavonoid glycosides from the flowering head of Chrysanthemum morifolium Ramat. The concentration of ionic liquid, extract time, microwave power and the matrix-to-solvent ratio were comprehensively optimized by Response Surface Method (RSM). The pretreated sample was dealt with HPLC-ESI-MS". The main components were identified as flavonoid glycosides including three luteolin glycosides, three apigenin glycosides, three kaempferide glycosides, and one acacetin glycoside according to the characteristic of the CID mass spectrometric pattern.Part 3 A method based on ESI-MS" was developed to analyze the fragmentation behaviors of furocoumarins and flavonoids. Six compounds from the fruit of Citrus medica L. var. sarcodactylis Swingle were rapidly identified by HPLC-ESI-MSn.In addition, the principle of HPLC-ESI-MSn technique and its recent application in medicinal plants was reviewed.