Electrocatalytic oxidation of D-penicillamine (D-PA) at the surface of 1-[4-(ferrocenyl-ethynyl) phenyl]-1-ethanone modified carbon paste electrode (4-FEPEMCPE) was thoroughly investigated using cyclic voltammetry (CV) and double step potential chronoamperometry methods in aqueous solution with various pH. It has been found that under optimum condition (pH 7.00) in cyclic voltammetry, the oxidation of D-PA occurred at a potential about 300 mV less positive than that unmodified carbon paste electrode. The electrocatalytic oxidation peak current of D-PA showed a linear dependent on the D-PA concentration and linear calibration curves were obtained in the ranges of 6.0×10-5 M – 1.6×10-3 M and 7.0×10-6 M – 2.3 ×10-4 M of D-PA concentration with cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods respectively. The detection limits (3 ) were determined as 4.6×10-5 M and 3.9×10-6 M. The proposed method was applied to determine D-PA in pharmaceutical preparation (capsules) and synthetic human serum by standard addition and recovery methods, respectively. The results obtained in the recovery study were comparable to those labelled.
