The electrooxidation of D penicillamine (D PA) has been studied in the presence of potassium iodide in various buffered aqueous solutions (4.00 ≤pH ≤9.00) at the surface of glassy carbon electrode using cyclic voltammetry, differential pulse voltammetry and chronoamperometry. It has been found that under optimum pH (pH 5.00) in cyclic voltammetry, the electrooxidation of D PA in the presence of potassium iodide as a homogeneous mediator occurred at a potential about 220 mV less positive than that in absence of potassium iodide at the surface of glassy carbon electrode. The homogeneous electrocatalytic oxidation current wave of D penicillamine was linearly dependent on the D-PA concentration and a linear calibration curve was obtained in the ranges 3.0 ×10–5 –1.5 ×10–3 M and 9.0 ×10–6 –1.2 ×10–4 M of D-PA with cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods, respectively. The detection limits (2σ) were determined as 3.0 ×10–5 and 3.5 ×10–6 M with CV and DPV, respectively. This method was also used for voltammetric determination of D PA in pharmaceutical preparation by standard addition method.
