title: Differentiation of Isomeric Ginsenosides by Using Electron-Induced Dissociation Mass Spectrometry.
abstract: Current phytochemical research on ginsengs focuses on the structural characterization and isomer differentiation of ginsenosides. In this Letter, electron-induced dissociation (EID) was initially investigated by analyzing isomeric ginsenosides. EID provided more structural information on their differentiation than collision-induced dissociation (CID) did. Glycosyl group migration previously observed in the CID of oligosaccharide ions could also be found in the EID of protonated Rg1. This rearrangement reaction would show substantial ambiguities in differentiating Rg1 from Rf. Although other charge carriers could alleviate this problem, the use of EID in dissociating deprotonated ginsenoside ions was superior to other techniques in terms of eliminating glycosyl group migration and generating diagnostic fragment ions for the differentiation of structural isomers. This study demonstrates a potential method to analyze natural products and thus help discover and evaluate novel compounds.
authors.affiliation: Department of Chemistry, The Chinese University of Hong Kong , Hong Kong SAR, P. R. China.
authors.forename: Y-L Elaine
authors.initials: YL
authors.lastname: Wong
authors.affiliation: Department of Chemistry, The Chinese University of Hong Kong , Hong Kong SAR, P. R. China.|Key Laboratory for TCM Quality Control Technology, Shandong Analysis and Test Centre, Shandong Academy of Sciences , Jinan, Shandong, 250014, P. R. China.
authors.forename: Xiangfeng
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Chemistry, The Chinese University of Hong Kong , Hong Kong SAR, P. R. China.
authors.forename: Wan
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Chemistry, The Chinese University of Hong Kong , Hong Kong SAR, P. R. China.
authors.forename: Ze
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Chemistry, The Chinese University of Hong Kong , Hong Kong SAR, P. R. China.
authors.forename: Y-L Winnie
authors.initials: YL
authors.lastname: Hung
authors.affiliation: Department of Chemistry, The Chinese University of Hong Kong , Hong Kong SAR, P. R. China.
authors.forename: Ri
authors.initials: R
authors.lastname: Wu
authors.affiliation: Department of Chemistry, The Chinese University of Hong Kong , Hong Kong SAR, P. R. China.
authors.forename: T-W Dominic
authors.initials: TW
authors.lastname: Chan