Standardization of P. ginseng and P. quinquefolius Root Extracts by HPLC-MS

Abstract

We develop a method on the basis of high-performance liquid phase chromatography–mass spectrometry (HPLC-MS) for determination of triterpene glycosides in ginseng extracts. In contrast to procedures based on HPLC with ultraviolet detection (HPLC-UV), commonly used for extract standardization, superior selectivity afforded by the developed method enables identification and quantitation of 23 major and minor ginsenosides. For this, in addition to using MS for highly selective detection of adduct ions composed of ginsenoside molecules and sodium and fragment sapogenin ions, we identify the conditions for chromatographic separation on a sorbent with grafted pentafluorophenyl groups. The effects that the temperature and mobile phase composition have on the selectivity of glycoside determination receive special attention here. For some pairs of compounds (F4/Rg6 and Rk3/Rh4), complete separation of chromatographic peaks is not achieved; nevertheless, even if present simultaneously, they can be determined owing to their different m/z ratios. The linearity ranges, equations for calibration curves, and analytical parameters (i.e., the limit of detection and reproducibility) are established for all analytes. The developed method is tested for standardization of reference extracts of Asian (P. ginseng) and American (P. quinquefolius) ginseng roots. For some ginsenosides, the content claimed by the manufacturer is at variance with the actual values, while for others the determined concentrations proved to be close to the claimed values. Additionally, we succeed in expanding the range of determinable ginsenosides, which is important for medical application of such extracts.