Differential Pulse Voltammetric Determination of Levodopa in Pharmaceutical and Biological Samples using NiO/graphene Oxide Nanocomposite Modified Graphite Screen Printed Electrode

A chemically modified electrode was prepared by incorporating NiO/graphene oxide nanocomposite into graphite screen printed electrode (NiO/GO/SPE) to determine levodopa. Cyclic voltammetry, differential pulse voltammetry and chronoamperometry were used to investigate the electrochemical behavior of levodopa at the chemically modified electrode. According to the results, NiO/GO/SPE showed high electrocatalytic activity for levodopa oxidation, producing a sharp oxidation peak current at about 240 mV vs Ag/AgCl reference electrode at pH 7.0. The peak current was linearly dependent on levodopa concentration over the range of 0.8–700.0 µM with the detection limit (3σ) of 0.2 µM. The proposed method was successfully applied as a rapid, highly selective, simple, and precise one to determine levodopa in biological fluids.