Prepare multi-wall carbon nanotubes modifying gold electrode(MWCNT/Au) and study this electrode electrocatalytic action to vitamin B12(VB12) and determining analytic condition of VB12 in the solution.In the mixture of 0.1 mol/L KCl as supporting electrolyte and phosphatic buffer solution(pH 7.0),a sensitive reduction peak of VB12 on MWCNT/Au was obtained by cyclic voltammetry.The potential peak for VB12 is-0.120V(vs.SCE).And the reduction peak currents of linear sweep voltammetry are linearly related to the concentration of VB12 in the range of 5×10-5mol/L～5×10-6 mol/L and 1×10-6mol/L～5×10-8 mol/L and the detect limit can reach 1.0×10-8 mol/L.This electrode has been applied to the direct determination of VB12 in sample with a recovery of 95.5%～108.5%.
