Analysis of metacycline by capillary electrophoresis

The development and validation of an optimized capillary electrophoresis me thod for the determination of metacycline in the presence of its related su bstances by capillary electrophoresis is shown, The influence of methanol a s organic modifier, buffer pH, buffer concentration, capillary length, colu mn temperature, Triton X-100 and methyl-beta -cyclodextrin was investigated . A central composite design was performed in order to optimize the method. The optimal separation conditions were: uncoated fused-silica capillary (3 9 cm total length, 31 cm effective length, 50 mum ID); as background electr olyte a solution of 160 mM sodium carbonate and 1 mM EDTA (pH 10.35)/methan ol (89:13 v/v); temperature, 15 degreesC; voltage, 12 kV. The method showed good selectivity, repeatability, linearity, and sensitivity. The limits of detection and quantitation are 0.024% and 0.06%, respectively, relative to a 2.5 mg/mL solution. Six commercial samples were analyzed quantitatively.