Voltammetric Determination of Penicillamine Using a Carbon Paste Electrode Modified with Multiwall Carbon Nanotubes In the Presence of Methyldopa as a Mediator.

A multiwall carbon nanotubes-modified carbon paste electrode (MWCNTs/MCPE) was fabricated and used to study the electrooxidation of penicillamine (PA) by electrochemical methods in the presence of methyldopa (MDOP) as a homogeneous mediator. The electrochemical oxidation of PA on the new sensor has been carefully studied. The kinetic parameters such as electron transfer coefficient, α, and catalytic reaction rate constant, K, were also determined using electrochemical approaches. The electrocatalytic oxidation peak current of PA showed a linear dependent on the PA concentrations and linear calibration curves were obtained in the ranges of 0.2-250.0 µM of PA concentration with square wave voltammetry (SWV) method. The detection limit (3σ) was determined as 0.1 µM. This sensor was also examined as a fast, selective, simple and precise new sensor for voltammetric determination of PA in real samples such as drug and urine.