Synergistic effect of α-Fe2O3/CuO heterojunction nanocomposite for enhanced electrochemical simultaneous detection of dopamine and ascorbic acid

Abstract Electrochemical sensing of ascorbic acid (AA) and dopamine (DA) has attracted considerable attention owing to their important roles in biological systems; therefore, precise determination of these analytes is essential for biological and clinical analysis. In this work, an α-Fe2O3/CuO nanocomposite was synthesized via a simple, effective and cost-effective hydrothermal method and employed as an integrated sensing material rather than using the individual metal oxides separately. The nanocomposite was immobilized on a glassy carbon electrode using Nafion as a binder, and its electrochemical behaviour was evaluated by cyclic voltammetry and differential pulse voltammetry. Under optimized conditions, well-defined responses were obtained for AA (500–7000 µM) and DA (300–15 000 µM), with corresponding detection limits of 79.1 and 25.9 µM, respectively. Tafel analysis demonstrated that the electrochemical oxidation of both analytes proceeds through a two-electron transfer mechanism, providing mechanistic insight into the sensing process. In practical analysis, the method yielded recovery values of 98.3% for AA and 99.8% for DA. Overall, these findings demonstrate that the α-Fe2O3/CuO-modified electrode provides a robust and reliable sensing platform with good detection performance, high selectivity and excellent stability for simultaneous quantification of AA and DA in real samples.