Direct electrochemical determination of pyruvate in human sweat by capillary zone electrophoresis

Capillary zone electrophoresis was employed for the determination of pyruva te in human sweat using electrochemical detection with a carbon fiber micro disk bundle electrode at a constant potential of 1.60 V vs. saturated calom el electrode. The optimum separation conditions are 3.6 x 10(-3) mol/L Na2H PO4-1.4 x 10(-3) mol/L NaH2PO4 (pH 7.2) for the buffer solution, and 18 kV for the separation voltage, The limits of detection of pyruvate are 8.0 x 1 0(-6) mol/L or 24 fmol (S/N = 3) for the injection voltage of 6 kV and the injection time of 10 s. The relative standard deviation is 2.0% for the mig ration time and 5.7% for the electrophoretic peak current. The method was a pplied to determining pyruvate in human sweat.