Diagnostic fragment-ion-based and extension strategy coupled to DFIs intensity analysis for identification of chlorogenic acids isomers in Flos Lonicerae Japonicae by HPLC-ESI-MSn

Jia-Yu Zhang, Qian Zhang, Ning Lic, Zi-Jian Wang, Jian-Qiu Lu,  Yan-Jiang Qiao , 

Abstract

A method of modified diagnostic fragment-ion-based extension strategy (DFIBES) coupled to DFIs (diagnostic fragmentation ions) intensity analysis was successfully established to simultaneously screen and identify the chlorogenic acids (CGAs) in Flos Lonicerae Japonicae (FLJ) by HPLC-ESI-MSn. DFIs, such as m/z 191 [quinic acid-H]?, m/z 179 [caffeic acid-H]? and m/z 173 [quinic acid–H–H2O]? were determined or proposed from the fragmentation patterns analysis of corresponding reference substances for every chemical family of CGAs. A “structure extension” method was then proposed based on the well-demonstrated fragmentation patterns and was successively applied into the rapid screening of CGAs in FLJ. Considering that substitution isomerism is a common phenomenon, a full ESI-MSn fragmentation analysis according to the intensity of DFIs has been performed to identify the CGA isomers. Based on the DFIs and intensity analysis, 41 peaks attributed to CGAs including 4 caffeoylquinic acids (CQA), 7 CQA glycosides, 6 dicaffeoylquinic acids (DiCQA), 10 DiCQA glycosides, 1 tricaffeoylquinic acids (TriCQA), 4p-coumaroylquinic acids (pCoQA)substances 

Nine CGA reference were purchased from Chengdu Biopurify Phtochemicals Ltd(Chengdu,China)