SIMULTANEOUS DETERMINATION OF 12 CONSTITUENTS OF I-TZU-TANG, A CHINESE HERBAL PREPARATION, BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY AND CAPILLARY ELECTROPHORESIS

A high-performance liquid chromatographic method and a capillary electrophoretic method for the separation of four anthraquinoids, five flavones, two carboxylic acids and one saponin in I-tzu-tang were developed. Detection at 254 nm with a linear gradient elution system of tetrabutylammonium bromide and dihydrogenphosphate buffer or with micellar electrokinetic chromatography with sodium dodecyl sulphate and sodium cholate buffer was found to be the most suitable approach for this analysis. The contents of these components in an unpretreated I-tzu-tang extract could be easily determined within 50 min by HPLC or 14 min by CE. The effect of buffers on this separation and the validation of these methods are discussed.