Optimization of the separation of a group of antifungals by capillary zoneelectrophoresis

Two simple, rapid, and efficient methods for the analysis of seven antifung al compounds have been developed by capillary zone electrophoresis. Resolut ions higher than 1.5 were obtained using 0.025 M phosphate buffer (pH 2.30) (analysis time close to 9 min) or 0.2 M formic acid (pH 2.15) (analysis ti me close to 6 min), with an applied voltage of 20 kV and a temperature of 3 0 degreesC. The highest sensitivity and selectivity can be obtained using p hosphate buffer but the shortest analysis times are achieved in the formic system. The analytical characteristics of the optimized methods were invest igated. The reproducibility obtained for migration times (RSD(n=10)less tha n or equal to1.0%) and peak areas (RSD(n=10)less than or equal to4.3%) was acceptable, but better reproducibilities were obtained when verapamil was u sed as internal standard (RSDn=10<0.4% for relative migration times and RSD n=10<less than or equal to>2.2% for peak area ratios). The lowest limit of detection was obtained for clotrimazole (0.12 mug/ml) and the highest for f luconazole and voriconazole (0.90 mug/ml). The lowest and the highest limit s of quantitation were, respectively, 0.40 mug/ml for clotrimazole and 3.00 mug/ml for fluconazole and voriconazole. (C) 2001 Elsevier Science B.V. Al l rights reserved.