Heart-cut capillary electrophoresis for drug analysis in mouse blood with electrochemical detection

A novel separation method, which interfaced capillary zone electrophoresis (CZE) and micellar electrokinetic capillary chromatography (MEKC), was developed for analysis of weak basic compounds. CZE was used as the first separation, from which the effluent components were transferred and further analyzed by MEKC. As the key to successful integration of CZE and MEKC, a new microhole interface was designed. On-line concentration strategies, namely pH junction and sweeping, were employed to avoid sample zone diffusion at the interface. For evaluation of the feasibility and effectiveness of the capillary electrophoresis (CE) system, basic cardiovascular drugs were used as model compounds. The resulting electropherogram was quite different from that of either CZE or MEKC separation. The relative standard deviations (RSDs) of peak height, peak area, and migration time were in the ranges of 2.7% to 4.5%, 1.3% to 3.6%, and 0.8% to 1.4%, respectively, and detection limits (signal/noise = 3) were 0.015 to 0.052 mg/L. The proposed method was successfully applied to the determination of basic cardiovascular drugs in mouse blood.