[Analysis of ginsenosides by high performance liquid chromatography/mass spectrometry/mass spectrometry(LC/MS/MS)]

Ginseng, one of the most popular medicinal herbs used in traditional Chinese medicines, has been studied to have biological effects attributing to its main constituents such as ginsenosides. There are more than 30 kinds of ginsenosides and some of them have similar polarity and structure. Thus, it is difficult to separate those ginsenosides with isocratic mobile phase owing to their similar polarity. A reversed-phase high performance liquid chromatographic method with gradient elution has been developed in this work. Nine ginsenosides can be separated by this method. Among them, five ginsenosides with different molecular weights can be determined by means of their molecular weight gained through LC/MS with an ESI interface. Re and Rd have the same Mw but belonging to two different kinds of ginsenosides. They can be differentiated from each other through their MS/MS gained by CID(collision induced decomposition) at the second stage quadrapole. Rc and Rb3 having the same molecular weight and belonging to the same kind of ginsenoside can be distinguished through their negative ion spectra gotten from LC/MS. So 9 ginsenosides can be determined by LC/MS/MS. This method can also be used to determine the ginsenosides contained in commercially available samples.