DETERMINATION OF SULFADIAZINE AND SULFAMETHOXAZOLE BY CAPILLARY-ELECTROPHORESIS WITH END-COLUMN ELECTROCHEMICAL DETECTION

Capillary electrophoresis (CE) with end-column electrochemical detecti on (EC) of sulfadiazine (SDZ) and sulfamethoxazole (SMZ) is described. Under the optimum conditions, SDZ and SMZ were separated satisfactori ly, and a highly sensitive and stable response was obtained at a poten tial of 1.1 V versus Ag/AgCl. Optimized end-column detection provides detection limits as low as 0.1 mu M for both compounds, which correspo nds to 0.024 and 0.021 fmol with peak efficiencies of 394000 and 33500 0 theoretical plates for SDZ arid SMZ, respectively. The calibration g raph was linear over three orders of magnitude. The relative standard deviations (n = 12) of peak currents and migration times were 2.3 and 2.7%, and 0.8 and 1.3%, respectively, for the two compounds. The propo sed method was applied to the analysis of tablets and human urine samp les with satisfactory results.