阴离子选择性耗尽进样-胶束扫集毛细管电泳法对痕量醋酸氢化可的松的测定

联用阴离子选择性耗尽进样和胶束扫集两种在线富集技术,建立了胶束毛细管电泳方法测定化妆品中醋酸氢化可的松的方法。讨论了SDS浓度、样品基体、进样电压、进水时间和进样时间对富集和分离的影响。优化的实验条件:以120 mmol/L SDS-20 mmol/L NaH2PO4(pH2.2)-10%(体积分数)甲醇为缓冲体系,分离电压-20 kV,进样电压-20 kV,进样时间80 s,进水时间200 s,测量波长250 nm。在该实验条件下,醋酸氢化可的松的富集倍数比普通毛细管电泳法提高了约173倍。方法的线性范围为0.05~5.0 mg/L,检出限为12.6μg/L。该方法用于化妆品中醋酸氢化可的松含量的测定,回收率为98%~105%,相对标准偏差均小于4.0%(n=4)。

On-line Sample Stacking for the Analysis of Hydrocortisone Acetate by Anion Selective Exhaustive Injection and Sweeping Micellar Electrokinetic Chromatography

Two on-line preconcentration techniques including anion selective exhaustive injection(ASEI),and sweeping micellar electrokinetic chromatographic(sweep-MEKC) method were used to analyze hydrocortisone acetate in cosmetics.The effect of SDS concentration,sample matrix,water injection time,sample injection time and sample injection voltage were optimized.The optimized conditions were as follows:the micellar buffer:120 mmol/L SDS-20 mmol/L NaH2PO4(pH 2.2)-10%(by volume) methanol;separation voltage:-20 kV;sampl...