Measurement of chloramphenicol by capillary zone electrophoresis followingend-column amperometric detection at a carbon fiber micro-disk array electrode

Capillary zone electrophoresis was employed for the measurement of chloramp henicol using end-column amperometric detection with a carbon fiber micro-d isk array electrode, at a constant potential of -1.00 V vs, saturated calom el electrode. The effect of oxygen in the buffer has been investigated. It is found that when the area of the carbon fiber electrode is smaller than 1 .1 mm(2), the interference of oxygen can be overcome. In this procedure deo xygenation is not necessary. The effect of pH, the concentration of the buf fer and the high separation voltage across the capillary on the migration t ime, electrophoretic peak current and separation efficiency has been studie d. The optimum conditions of separation and detection are 8.4 x 10(-4) mol/ l HOAc-3.2 x 10(-3) mol/l NaOAc for the buffer solution, 20 kV for the sepa ration voltage, 5 kV and 5 s for the injection voltage and the injection ti me, respectively. The calibration plot was found to be linear in the range 5 x 10(-6) to 1 x 10(-3) mol/l and the limit of detection is 9.1 x 10(-7) m ol/l or 1.4 fmol (S/N = 2). The relative standard deviation is 1.1% for the migration time and 2.3% for the electrophoretic peak current. The method w as applied to the determination of chloramphenicol in human serum. (C) 2000 Published by Elsevier Science B.V. All rights reserved.