[Two dimensional capillary zone electrophoresis/micellar electrokinetic capillary chromatography for the analysis of drugs and their enantiomers in urine samples].

A new two dimensional method, which interfaced capillary zone electrophoresis (CZE) and micellar electrokinetic capillary chromatography (MEKC) by a polytetrafluoroethylene (PTFE) tube with a hole of 30-40 microm diameter on the top, was developed for the analysis of drugs and their enantiomers. The CZE was used as the first dimensional separation, from which the eluting components were transferred and further analyzed by MEKC. Online dual concentration method, pH junction-sweeping, was used to avoid sample zone diffusion at the interface. The separation efficiencies and detection limits were (2.8-4.3) x 10(4)/m and 0.015-0.052 mg/L, respectively. The proposed method has successfully demonstrated that in the separation of four drugs and their enantiomers in urine samples, the relative standard deviations (RSDs) of peak area and migration time were in the ranges of 1.7%-3.8% and 1.3%-4.6%, respectively. The method was proved to have good reproducibility, high sensitivity and resolution, large peak capacity. It is reliable and suitable to separate and determine multi-drugs and their enantiomers in urine samples simultaneously.