Separation of Astragalus saponins by reversed phase high performance liquid chromatography and evaporative light scattering detection.

A new HPLC method permitted the separation of 13 triterpene lycosides isolated from different Astragalus species within 40 min. A water/acetonitrile gradient was used as eluent and 5 μm RP-18 material as stationary phase. By using an evaporative light scattering (ELS) detector, the main saponins of A. membranaceus could be detected at levels as low as 20.0 μg·mL⁻¹. This method facilitated distinction of different Astragalus species as well as the analyses of market products containing A. membranaceus. The results showed variations from 0.019 to 0.184% in the total saponin content of the market products. [ABSTRACT FROM AUTHOR]