Poly(bromocresol green) modified screen-printed carbon electrode for selective voltametric detection of uric acid

A poly(bromocresol green)-modified screen-printed carbon electrode (PBCG/SPCE) was fabricated through electropolymerization for the electrochemical determination of uric acid (UA). The modified electrode was characterized using cyclic voltammetry and Fourier transform infrared spectroscopy, confirming successful formation of the poly(bromocresol green) film on the electrode surface. Electrochemical characterization revealed an approximately 50% increase in electroactive surface area compared with the bare electrode, which contributed to improved electron-transfer kinetics and enhanced oxidation peak current for UA detection. The electrocatalytic activity of the polymer film was attributed to facilitated charge transfer and adsorption interactions between UA and the functional groups of the polymeric coating. Differential pulse voltammetry was employed for quantitative determination of UA in 0.1 M phosphate buffer solution (pH 7.0). Under optimized conditions, the sensor exhibited a linear response over the concentration range of 0.1-1000 µM with a detection limit of 0.0212 µM and a limit of quantification of 0.0638 µM. In the presence of ascorbic acid, the modified electrode showed moderate selectivity toward UA, with a selectivity coefficient of 0.23. The sensor also demonstrated good operational stability, with coefficient variations of 2.44% for peak current and 0.39% for peak potential, as well as good reproducibility and repeatability, with relative standard deviations of 2.67% and 2.91%, respectively. Finally, the developed PBCG/SPCE sensor was successfully applied to the determination of UA in human urine samples, indicating its potential utility for low-cost and sensitive clinical analysis.