An anodized nanostructure of Ni/Cu alloy synthesized in ethaline for electrocatalytic oxidation and amperometric determination of l-carnitine

Developing simple techniques for quick detecting and accurate quantification of pharmaceuticals and biologically important compounds are critical toward the public health and the quality of life. In the present paper, we develop a sensitive amperometric technique for detection and quantification of l-carnitine on an anodized Ni/Cu alloy electrode. The modified electrode in this study is prepared via an anodizing process applied directly on Ni/Cu alloy electrodes, resulting in formation of a nanostructured modifier layer composed of nickel and copper oxides. Voltammetric studies revealed that the modified electrode catalytically oxidizes l-carnitine via an electrochemical reaction followed by a chemical reaction producing the primary redox species (EC′) mechanism. Comparison of the modified Ni/Cu alloy with the anodized pure nickel and copper electrodes indicated that the presence of copper at the electrode surface prevents the adsorption of the oxidation products at the electrode surface and retains its catalytic activity. Moreover, a kinetic model based on the electrochemical generation of Ni(III) active sites and their subsequent reduction by l-carnitine is proposed. Furthermore, a sensitive, simple and fast-response amperometric technique is developed for the analysis of l-carnitine with a detection limit of 7.08 μmol L−1. The developed amperometric technique is capable of the direct detection and quantification of the drug in different pharmaceuticals forms and human serum samples without any pretreatment procedure.