title: Quasi-MSn identification of flavanone 7-glycoside isomers in Da Chengqi Tang by high performance liquid chromatography-tandem mass spectrometry.
abstract: BACKGROUND
  Da Chengqi Tang (DCT) is a common purgative formula in Chinese medicine. Flavanones are its major active compounds derived from Fructus Aurantii Immaturus. The present study developed an LC-MS/MS method to characterize two pairs of flavanone 7-glycoside isomers, i.e., hesperidin versus neohesperidin and naringin versus isonaringin.
  
  
  METHODS
  After solid phase purification, components in sample were separated on a Agilent zorbax SB-C18 (5 microm, 250 mm x 4.6 mm) analytical column. ESI-MS and quasi-MSn were performed in negative ion mode to obtain structural data of these two pairs of flavanone 7-glycoside isomers. Moreover, UV absorption was measured.
  
  
  RESULTS
  There was no intra-pairs difference in the UV-Vis and MS/MS spectra of the two pairs of 7-glycoside isomers, whereas the mass spectrometry fragmentation pathways between pairs were different.
  
  
  CONCLUSIONS
  The present study developed a LC-MS/MS method to explore the inter- and intra-pair difference of two pairs of flavanone 7-glycoside isomers.
authors.affiliation: Key Laboratory of Drug Quality Control and Pharmacovigilance (Ministry of Education), China Pharmaceutical University, Nanjing, Jiangsu, PR China. fengguoxu@gmail.com
authors.forename: Fengguo
authors.initials: F
authors.lastname: Xu
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.forename: Zunjian
authors.initials: Z
authors.lastname: Zhang
authors.forename: Cheng
authors.initials: C
authors.lastname: Yang
authors.forename: Yuan
authors.initials: Y
authors.lastname: Tian