Study on separation of aristolochic acid I and II by micellar electrokinetic capillary chromatography and competition mechanism between SDS and β-cyclodextrin

In this study, a rapid MEKC method using 40mM sodium borate buffer containing 50 mM SDS as surfactant was developed for the analysis of aristolochic acid (AA) in Aristolochia plants. Baseline separation of AA-I and AA-II was achieved within 3 min with high separation efficiency, satisfactory sensitivity, repeatability, and recovery. Resolution between AA-I and AA-II is above 5 and great performance with higher than 200 000 theoretical plate numbers was obtained. The detection limits (based on 3 S/N) were both 1.0 mu g/mL. Two kinds of AA in 35 herbal samples of Aristolochia plants were successfully determined. The competition mechanism between P-CD and SDS was also investigated by changing the content ratio of P-CD and SDS.