A glassy carbon electrode modified with 1-benzyl-4-ferrocenyl-1H-[1,2,3]-triazole (BFT) and carbon nanotubes have been applied to the electrocatalytic oxidation of D-penicillamine (D-PA) which reduced the overpotential by about 470 mV with obviously increase the current response. Due to its strong electrocatalytic activity towards D-PA, the modified electrode can resolve the overlapped voltammetric waves of D-PA and tryptophan (TRP) into two well-defined voltammetric peaks with peak-to-peak separation in potentials of about 270 mV. This property allows to selective determination of D-PA in the presence of TRP. The transfer coefficient (a) for the electrocatalytic oxidation of D-PA and diffusion coefficient of this substance under the experimental conditions were also investigated. In phosphate buffer solution (PBS) of pH 8.0, the oxidation current increased linearly with two concentration intervals of D-PA, one is 1.0 to 10.0 μM and, the other is 10.0 to 800.0 μM. The detection limit (3σ) obtained by square wave voltammetry (SWV) was 0.1 μM. The proposed method was successfully applied to the determination of D-PA, and TRP in real samples.
