Determination of gentiopicroside in extracts of Centaurium erythreae and Gentiana lutea by micellar electrokinetic capillary chromatography

Micellar electrokinetic capillary chromatography has been developed as a pr omising method for the determination of gentiopicroside in plant samples. T he separation conditions have been optimised with respect to the different parameters including SDS concentration, pH, and ion strength of the backgro und electrolyte, and temperature of capillary. A buffer consisting of 100 m M SDS in 20 mM sodium dihydrogen phosphate, 20 mM disodium tetraborate pH 8 .6 was found to be the most suitable electrolyte for this separation. The a pplied voltage of 28 kV (positive polarity) and the temperature of capillar y 20 degrees C gave the best analysis of gentiopicroside. The linear detect ion range for concentration versus peak area for the assay is from 5 to 500 mu g. mL(-1) (correlation coefficient 0.9998) with a detection limit of 0. 3 1.18. . mL(-1). The inter-day reproducibility of the peak area was below 2.5% and the inter-day reproducibility of the migration time was below 0.16 %.