Capillary zone electrophoresis with end-column amperometric detection for the determination of glutathione at a gold/mercury amalgam microelectrode without deoxygenation

Capillary zone electrophoresis was employed to the analysis of glutathione by using end-column amperometric detection with a gold/mercury amalgam microelectrode at a constant potential of 0.02 similar to 0.06 V vs. SCE. In this procedure deoxygenation is not necessary. The calibration plot was found to be linear over 4 orders of magnitude and the limit of detection was 6.3x10(-7) mol l(-1) (or 126 amol). The effect of the concentration of the buffer, and the high separation voltage across the capillary on the migration time and separation efficiency, and the dependence of the injection conditions on the detection signal, the separation efficiency and the coulometric efficiency have been investigated. The method was applied to the determination of glutathione in human blood and erythrocytes.