Migration behaviour of benzodiazepines in micellar electrokinetic chromatography

The migration behaviour of a series of benzodiazepines in micellar electrokinetic chromatography was studied using three kinds of surfactants, i.e. sodium dodecyl sulphate (SDS), dodecyl trimethylammonium bromide (DoTAB) and bile salts. With SDS and DoTAB, retention factors were found to be too high to obtain adequate resolution. Both bile salts used in this study, sodium cholate and sodium deoxycholate, provided a satisfactory range of retention factors. Moreover, selectivity of the separation could be manipulated by combining these two bile salts in varying ratios.