Electrodeposition of nickel wrinkled nanostructure from choline chloride:Urea deep eutectic solvent (reline) and application for electroanalysis of simvastatin

Abstract

Wrinkled nanostructure of nickel was electrodeposited from a deep eutectic solvent comprising choline chloride and urea (reline) under golvanostatic conditions. Field emission scanning electron microscopic images were taken to evaluate the shape and size of the nickel nanostructure. The nickel nanostructure was then converted into the corresponding oxides, and the kinetics of charge transfer across the interface of the nanostructured oxides/an alkaline electrolyte was then studied. The electron transfer coefficient and apparent rate constant for the NiIII/NiII transition in the alkaline electrolyte were attained as 0.53 and 1.0 s−1, respectively. The interaction conditions of nickel redox sites on the surface were also discussed. As an application, electrocatalytic oxidation of simvastatin was studied on the nickel wrinkled nanostructure in the alkaline solution. The oxidation process and its kinetics were investigated by cyclic voltammetry and chronoamperometry. Voltammetric studies indicated that simvastatin was oxidized by NiIII species via an electrocatalytic mechanism. For the electrooxidation of simvastatin, a rate constant of 3.21 × 103 cm3 mol−1 s−1 and an electron transfer coefficient of 0.45 were obtained, while simvastatin diffused in the electrolyte with a diffusion coefficient of 1.80 × 10−6 cm2 s−1. Finally, simvastatin was determined by the nickel wrinkled nanostructure using an amperometry method with a limit of detection of 4.88 μmol L−1 and a calibration sensitivity of 0.035 A L mol−1 cm−2. The determination method was applied for determination of the drug in tablets.