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 x 10(-5) M-2 x 10(-3) M, 6 center dot 5 x 10(-5) M-1 center dot 1 x 10(-3) M and 7 x 10(-6) M-1 center dot 6 x 10(-4)M, 7 x 10(-6) M-2 x 10(-4) M of D-PA are obtained from CV and DPV methods for FCCPE and 2,7-BFEFMCPE, respectively. The detection limits (3 sigma) were determined as 5 center dot 4 x 10(-5) M and 6 center dot 3 x 10(-5) M in CV and 6 center dot 2 x 10(-6) M and 6 center dot 8 x 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.