Simultaneous Electrochemical Determination of Uric Acid, Xanthine, and Hypoxanthine Using AgNPs/MIL-101(Cr) Modified Electrode

This paper presents silver nanoparticles supported by the Matérial Institute Lavoisier-101 (AgNPs/MIL-101(Cr)) for electrochemical determination of uric acid (URA), xanthine (XAT), and hypoxanthine (HPX). The prepared AgNPs/MIL-101 was characterized using X-ray diffraction, nitrogen adsorption/desorption isotherms, transmission electron microscopy, and electrochemical impedance spectroscopy. It was found that the Ag metal particles were around 13.4 nm, highly dispersed on MIL-101(Cr). The electrochemical performance of AgNPs/MIL-101(Cr) modified glassy carbon electrode (AgNPs/MIL-101(Cr)/GCE) was investigated. It was found that the electrochemical sensor modified with AgNPs/MIL-101(Cr), having an Ag molar ratio to Cr of approximately 0.079, exhibits good electrocatalytic activity towards the oxidation of URA, XAT, and HPX. The AgNPs/MIL-101(Cr)/GCE was used to simultaneously determine URA, XAT, and HPX by differential pulse voltammetry. Under optimal conditions, calibration curves for the three analytes were obtained over the 0.50–4.93 μM range. The limit of detection for URA, XAT, and HPX is 0.36, 0.22, and 0.25 μM, respectively. This method was used to analyze URA, XAT, and HPX in human urine; the results were not statistically different from the standard HPLC method. The proposed electrochemical sensor is robust and straightforward, with reasonable accuracy and precision for measuring URA, XAT, and HPX concentrations.