Abstract

This paper was designed to develop a novel method via ultra-performance liquid chromatography-electrospray ionization-quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-QTOF-MS^E) for the analysis and identification of saponins from extract of Ziziphi spinosae Semen (ZSS). The possible fragmentation pathways were proposed on the basis of MS^E data. In results, 13 saponins, including two unknown compounds, were identified and they were divided into two groups on the basis of mass spectral analysis. Compound 1~6, which were of keto-dammarane type triterpene saponin, underwent McLafferty-type (or McLafferty) rearrangement, and compound 7~13, which were of dammarane type triterpene saponin, underwent retro Diels-Alder (RDA) cleavage. The results testified that the developed method was useful to rapidly and simultaneously identify the constituents in ZSS. In this paper, the principles of McLafferty-type (or McLafferty) rearrangement were firstly utilized to elucidate the proposed fragmentation pathways of saponins from ZSS.

Key words: Ziziphi spinosae semen, ultra-performance liquid chromatography (UPLC), quadrupole time-of-flight tandem mass spectrometry (QTOF-MS^E), retro Diels-Alder cleavage, McLafferty-type rearrangement.