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 F 4, Rg 3, Rg 5, Rg 6, Rk 1, Rk 3, Rs 3, Rs 4, and Rs 5. The method used a C 18-bonded silica column with a CH 3CN/H 2O/CH 3COOH gradient elution. (20 R) and (20 S) epimers and geometric isomers at the C-20 position of ginsenosides, which are not generally separated by amino columns, were now clearly separated.