Dopamine modified electrodes for indirect voltammetric determination of magnesium ions

Abstract

This article outlines the fabrication process of an electrochemical sensor designed for the innovative determination of magnesium ions based on the electrochemistry of dopamine. The sensor operates under voltammetric conditions, accounting for variations in the electrochemical reversibility of immobilized dopamine in the presence of magnesium ions under conditions of square-wave voltammetry. The immobilization of dopamine on the glassy carbon electrode is achieved through the electrochemical oxidation of its side amino group, leading to covalent grafting onto the electrode surface. All stages of the proposed electrode surface modification procedure were carefully optimized. The dopamine sensor exhibited a linear response in the concentration range of magnesium ions from 0.1 to 10 mmol L−1, with a limit of detection (LOD) value equal to 1.3 × 10−5 mol L−1. To validate the electroanalytical significance of the developed methodology, real food supplement samples were quantitatively analyzed, demonstrating a highly satisfactory rate of recovery. The proposed voltammetric method serves as a simple and cost-effective procedure for the indirect determination of magnesium ions. Additionally, this approach allows for the analysis of real samples without the need for time-consuming preparation steps, as the complex matrices of food supplement samples did not adversely affect the registered currents.