Electrochemical sensing of D-penicillamine on modified glassy carbon electrode by using a nanocomposite of gold nanoparticles and reduced graphene oxide

A new electrochemical sensor was developed for determination of D-penicillamine using glassy carbon electrode which had been modified by gold nanoparticles–reduced graphene oxide nanocomposite (AuNPs/RGO/GCE) in aqueous solution. Cyclic voltammetry, transmission electron microscopy and electrochemical impedance spectroscopy were used for characterization of the modified electrode. The results indicated that the kinetic of oxidation reaction of D-penicillamine at the surface of the electrode was controlled by both diffusion and adsorption processes. In 0.1 mol L−1 phosphate buffer (pH 2.0), the oxidation current increased linearly with concentration of D-penicillamine with a linear range of 5.0 × 10−6 to 1.1 × 10−4 mol L−1 and regression coefficient of R2 = 0.9972. Theoretical detection limit, defined based on 3σ of the blank signal (n = 9) divided by the slope of the linear regression equation, was 3.9 × 10−6 mol L−1D-penicillamine using differential pulse voltammetry. The developed method was successfully applied to the determination of D-penicillamine in pharmaceutical formulation and blood serum samples.