Standartization of P. ginseng and P. quinquefolius root extracts by liquid chromatography-mass spectrometry

Abstract

An approach to detection of triterpene glycosides in ginseng extracts is developed using high performance liquid chromatography/mass spectrometry (HPLC-MS). Enhanced selectivity compared to commonly used HPLC-UV techniques provides simultaneous registration of chromatographic peaks and determination of 23 major and minor ginsenosides. For this purpose, in addition to the use of highly selective MS detection of adduct ions of sodium ginsenoside molecules and fragmentary sapogenin ions, special conditions of chromatographic separation on a sorbent modified with pentafluorophenyl (PFP) groups were specified. The effect of column temperature and mobile phase composition on the separation selectivity of glycosides was also studied. Though we failed to achieve complete chromatographic separation of the peaks for several compounds (F4 and Rg6, Rk3 and Rh4), their determination appeared possible in case of their joint attendance due to registration of the signals that differ in the value ofm/zratio. For all studied compounds, the linearity ranges and calibration equations along with the metrological characteristics such as the detection limit and reproducibility were determined. The developed approach was tested in standardization of the reference extracts of Asian (P. ginseng) and American (P. quinquefolius) ginseng roots. For some ginsenosides, the content declared by the manufacture did not match the actual content, but for others the concentrations were close to the declared values. Moreover, we managed to expand the range of ginsenosides under control which is rather important for their use in medicine.