Optimized separation of pharmacologically active flavonoids from Epimedium species by capillary electrophoresis

Sixteen pharmacologically active flavonoids and one phenylethanoid glucoside isolated from Epimedium species were analyzed by capillary electrophoresis in different buffer systems of AMPSO, CAPS, phosphate and berate. The berate system proved to be the best. After optimization and studies of the effect of berate and SDS concentrations, organic modifier, voltage and effective capillary length on migration of the analytes, 14 flavonoids and one phenylethanoid glucoside were baseline separated within 20 min in the buffer system of 20 mM berate and 48 mM SDS containing 1 mM 1, 3-diaminopropane at pH 8.5 and at the detection wavelength of 254 nm. The two-marker (xanthene-9-carboxylic acid/meso-2,3-diphenylsuccinic acid) technique and the computer program based on MATLAB were applied to improve the repeatability of analysis and to confirm the reliability of identification between two successive compounds. The reliability of identification was enhanced up to 25-fold for the analytes when the migration indices were used with the two-marker technique.