Liquid chromatographic determination of less polar ginsenosides in processed ginseng

Reversed-phase LC with an evaporative light scattering detector (ELSD) is used for the determination of less polar ginsenosides in processed ginseng. These ginsenosides include ginsenosides F4, Rg3, Rg5, Rg6, Rk1, Rk3, Rs3, Rs4, and Rs5. The method used a C18-bonded silica column with a CH3CN/H2O/CH3COOH gradient elution. (20R) and (20S) epimers and geometric isomers at the C-20 position of ginsenosides, which are not generally separated by amino columns, were now clearly separated.