Capillary zone electrophoresis was employed for the determination of pyrido
xine using end-column amperometric detection with a carbon fiber microelect
rode at a constant potential of 0.72 V (vs. SCE). The optimum conditions of
separation and detection are 1.0 x 10(-2) mol/L NH4Cl-1.0 x 10(-2) mol/L N
H3 for the buffer solution, 10 kV for the separation voltage, 5 kV and 10 a
for the injection voltage and the injection time, respectively. The limit
of detection is 1.2 x 10(-6) mol/L or 3.5 fmol (S/N=2). The relative standa
rd deviation is 1.3 % for the migration time and 3.4% for the electrophoret
ic peak current. The method was applied to determining pyridoxine in human
urine.