Separation and determination of the active ingredients in tablets of composite sulphonamides by capillary zone electrophoresis with amperometric detection

A simple, reliable and reproducible method, based on capillary electrophoresis with amperometric detection, for separation and determination of the active ingredients in tablets of the composite sulphonamides is described in this paper. A carbon-disc electrode used as working electrode for three analytes exhibits good responses at +1275 mV (vs. Ag/AgCl). Under the optimum conditions, three analytes were base-line separated, and excellent linearity was obtained in the concentration range from 3.0 x 10(-6) to 5.0 x 10(-4) mol/l. The detection limit was 1.0 x 10(-6), 1.0 x 10(-6), and 8.0 x 10(-7) mol/l for sulphadiazine, sulphamethazine and trimethoprim, respectively. This method was successfully used in the analysis of actual pharmaceutical samples, and the assay results were satisfactory. (C) 1999 Elsevier Science B.V. All rights reserved.