The capillary electrophoresis separation of benzodiazepine drug using dextran sulfate and SDS as running buffer

Capillary electrophoresis has been applied the analyses of many clinical drugs due to its rapid, high-resolution separation. In this study, electrokinetic chromatography involving the combination of SDS and dextran sulfate, which are synthetic polymers, was examined in order to obtain high resolution. Use of 2% dextran sulfate (10,000 molecular weight), 20 mm SDS running buffer containing boric acid solution (pH 9.2) and a silica capillary (inner diameter of 75 micro m, effective length of 50 cm, 57 cm overall length) afforded separation of 10 kinds of benzodiazepines. The detection limit was 0.2 micro g/mL; additionally, reproducibilities were de fi ned as the peak height and migration time. The average peak height was 5.92% (2.46-17.61), whereas the average migration time was 0.44% (0.18-0.76; n = 5). This separations system can be applied to the analysis and measurement of other pharmaceuticals as well.