Determination of effective ingredients in compound sulfamethoxazole tablets by capillary electrophoresis with amperometric detection

A high-performance capillary electrophoresis with amperometric detection (CE-AD) method has been employed for the determination of three antibacterial sulfa components, namely sulfamethoxazole (SMZ) sulfadiazine (SD and trimethoprim (TMP). The effects of several factors on CE-AD were investigated. Under the optimum conditions, the three components could be well separated within 14 min in a 70-cm length capillary at the separation voltage of 18 kV, injection time of 6 s in a 13 mmol/L borax -18 mmol/L potassium dihydrogen phosphate running buffer (pH 5.8). The above three analytes had good linear relationship between peak current and concentration of analytes at the range of 5 x 10(-4) -5 x 10(-2) g/L, 5 x 10(-4) -0.1 g/L, and 5 X 10-4 -5 x 10(-2) g/L, respectively, and the detection limits (S/N = 3) ranged from 5.1 x 10(-5) to 8.0 x 10(-5) g/L for all analytes. This proposed method has been successfully applied for the determination of the main effective components in Compound Sulfamethoxazole Tablets.