Highly selective monitoring of in-source fragmentation sapogenin product ions in positive mode enabling group-target ginsenosides profiling and simultaneous identification of seven Panax herbal medicines

In-source fragmentation of ginsenosides in the positive ESI mode (pISF-G) frequently occurs, which results in little fragment information useful for the structural elucidation. We are aimed to unveil the genesic mechanism and explore its potential significance in quality control of Ginseng and the related compound formulae. By applying six high-resolution mass spectrometers from Agilent, Waters, and Thermo Fisher, we could primarily demonstrate the susceptibility of pISF-G. The ion clusters in the positive full-scan MS1 spectra were generated from the protonated sapogenins by successive elimination of H2O, and showed specificity for ginsenoside classification. Selective ion monitoring (SIM) of the sapogenin product ions could delineate group-target ginsenoside profiles from Ginseng. A high-selectivity characteristic chromatogram (CC) was elaborated for Ginseng, on the Vion™ IMS-QTOF mass spectrometer by IM (ion mobility) separation and quadrupole filtering of four sapogenin fragments (m/z 407.37/CCS 206.24 Å2; m/z 423.36/CCS 211.26 Å2; m/z 439.36/CCS 209.60 Å2; m/z 457.37/CCS 217.81 Å2). Chemometric analysis, based on the CC data of seven Ginseng drugs (P. ginseng, P. quinquefolius, P. notoginseng, Red ginseng, leaf of P. ginseng, P. japonicus, and P. japonicus var. major), disclosed 35 marker compounds. We could readily discriminate among P. ginseng, P. quinquefolius, and P. notoginseng, in 15 different compound formulae by identifying these marker compounds on both the Vion IMS-QTOF and QTrap 4500 mass spectrometers. Conclusively, SIM of the pISF-G sapogenin product ions renders a new concept of CC enabling the group-target profiling of ginsenosides and authentication of Ginseng and the related compound formulae.