Separation of promethazine and thioridazine using capillary electrophoresis with end-column amperometric detection

Promethazine and thioridazine were separated and detected by capillary electrophoresis with end-column amperometric detection. The influence of pH Value on oxidation potential, the peak current and the resolution were studied and the following conditions was selected: 0.03 M Na2HPO4 and 0.015 M citric acid at pH 3.0, detection potential at 1.10 V. The detection limits of these two substances were in the range of 10(-8) mol/l. The linear range spanned two to three orders of magnitude. This method was applied to the detection of promethazine and thioridazine spiked in urine. (C) 1999 Elsevier Science B.V. All rights reserved.