Voltammetric sensor for D-penicillamine determination based on its electrocatalytic oxidation at the surface of ferrocenes modified carbon paste electrodes

Electrocatalytic oxidation of D-penicillamine (D-PA) at the surface of ferrocene modified carbon paste electrode (FCCPE) was thoroughly investigated in aqueous solution with various pH. The performance of this modified electrode was compared with those of 2,7-bis(ferrocenyl ethyl) fluoren-9-one modified carbon paste electrode (2,7-BFEFMCPE). In the optimum condition, the oxidation of d-PA at the surface of FCCPE and 2,7-BFEFMCPE is occurred about 480 and 320 mV less positive than that unmodified carbon paste electrode, respectively. The linear dynamic ranges 6 × 10−5 M-2 × 10−3 M, 6·5 × 10−5 M-1·1 × 10−3 M and 7 × 10−6 M-1·6 × 10−4M, 7 × 10−6 M-2 × 10−4 M of D-PA are obtained from CV and DPV methods for FCCPE and 2,7-BFEFMCPE, respectively. The detection limits (3σ) were determined as 5·4 × 10−5 M and 6·3 × 10−5 M in CV and 6·2 × 10−6 M and 6·8 × 10−6 M in DPV determinations for FCCPE and 2,7-BFEFMCPE, respectively. The proposed method was applied in a highly sensitive determination of d-PA in drug and human synthetic serum samples by standard addition and recovery methods, respectively.