Abstract
A sensitive and simple micellar electrokinetic chromatography (MEKC) method was developed for the determination of the antiepileptic drug carbamazepine (CBZ) using a sweeping on‐line concentration method with photodiode array detection. The effect of pH, concentration of the running buffer solution, organic modifier, applied voltage and injection time on the concentration efficiency and separation was investigated. An untreated fused‐silica capillary was used (50 cm; effective length, 40 cm, 75 µm i.d.) for the analysis. The background solution (BGS) was 50 mmol · L−1 NaH2PO4 (pH 3.0) containing 100 mmol · L−1 SDS and 20% acetonitrile (5.82 ms · cm−1) with an applied voltage of −20 kV at 25°C. Sample introduction was performed at 0.5 psi for 90 s with diode array detection at 214 nm. For the method, the calibration curve was linear over a range of 0.5–40 µg · mL−1 for CBZ with a correlation coefficient of 0.998. The detection limit (S/N=3∶1) of CBZ was 0.10 µg · mL−1. About 100‐fold improvement in concentration sensitivity was achieved in terms of peak height by the sweeping method compared to conventional injection method. The sweeping‐MEKC method has been successfully applied to the analysis of CBZ in tablet and human serum.
Acknowledgments
This project is sponsored both by a grant from the Natural Science Foundation of Hebei, P. R. China (B2006000413) and by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry.