One-step admicelle to cyclodextrin sweeping of toxic aristolochic acids by capillary electrophoresis

One-step admicelle to cyclodextrin sweeping (ACDS) method in capillary electrophoresis (CE) has been developed for the separation and preconcentration of toxic aristolochic acids (AAs) by applying cetyltrimethylammonium chloride (CTAC) between the critical micelle concentration and critical surface aggregation concentration. The analytes were captured into the CTAC admicelles, after the more stable inclusion complexes were formed, the release and preconcentration of the analytes could be realized. The CE enrichment parameters, such as the types of cationic surfactants and cyclodextrins (CDs), the concentration of cationic surfactants, disodium tetraborate decahydrate (borax) and CDs, the volume ratio of acetonitrile (ACN) in background electrolyte (BGE) and the sample injection time were optimized systemically. The optimal BGE was composed of 20 mM borax, 10 mM γ-CD and 10 % (v/v) ACN, the sample matrix consisted of 0.2 mM CTAC, 20 mM borax and five analytes. The limit of detection of this method was 3–6 ng/mL, and good linearity values (R2) were obtained for five AAs in the range of 0.997–0.999. Applying optimized conditions, the enrichment efficiencies of five AAs were enhanced with the sensitivity enrichment factors of 30–68. The sweeping approach was successfully applied to the determination of A, B, Ⅶa, C and D in Aristolochia and Asarum samples, which could provide a potential in the enrichment of the other toxic compounds.