Highly sensitive non-enzymatic electrochemical sensor for uric acid detection using copper oxide nanopebbles-modified glassy carbon electrode

A highly sensitive mediator-dependent electrochemical non-enzymatic biosensor for uric acid sensing was developed using copper oxide nanopebbles as an effective electrochemical sensing platform. For this purpose, CuO nanopebbles were prepared using a simple wet chemical route and employed to fabricate CuO-modified glass carbon (GC) electrode with chitosan as a binder to form GC/CuO/Chitosan. The electrochemical oxidation and reduction of uric acid at the electrode–electrolyte interface were facilitated by the electrocatalytic behaviour of CuO nanopebbles. Upon employing differential pulse voltammetry, the fabricated electrode detected uric acid over a broad linear range of 0.1–1.2 mM with a high sensitivity of 0.020 µA µM⁻¹ and a low limit of detection of 28.2 nM. The developed electrode offers high stability over a period of 14 days with good repeatability (1.61 % RSD) and reproducibility (2.27 % RSD). Finally, the fabricated electrode was tested to quantify the spiked uric acid concentrations in synthetic urine samples to analyse the practical ability of the electrode in real-world analysis, and the recovery results (99.4–100.7 %) were satisfactory. Taken together, the fabricated CuO nanopebble-based GC electrode could be used as a promising candidate for sensing and quantifying ultra-low levels of uric acid in urine samples.