A cost-effective disposable graphene-based sensor for sensitive and selective detection of uric acid in human urine

A rapid and facile method has been developed for uric acid (UA) sensing in human urine. The graphite pencil electrode's (GPE) sensitivity and electrochemical activity for sensing uric acid in human urine were enhanced by the electrochemically reduced graphene oxide on GPE in acetate buffer (ac-dERGO-GPE). Acetate, medium-supported graphene oxide reduction, is more facile, fast, and sensitive than water-dispersed graphene oxide. The surface of the modified and bare electrode was thoroughly investigated using the Fourier transform-infrared (FTIR), Field emission-scanning electron microscopy (FE-SEM), cyclic voltammetry (CV), square wave voltammetry (SWV), and electrochemical impedance spectroscopy (EIS). The electroactive surface area of the modified electrode was significantly improved from 0.0686 cm2 to 0.3615 cm2. The graphene layers greatly enhanced the electroactive surface area and the sensitivity of the ac-dERGO/GPE. A linear response was observed for UA in the range of 0.200 μM–22.0 μM with a 0.996 regression coefficient and a low detection limit of 0.037 μM. The modified electrode retained its response intact in the presence of the potential interferences and successfully applied for UA sensing in human urine. The ac-dERGO/GPE sensor, due to its facile fabrication, low cost, excellent sensitivity, and high selectivity could be a potential candidate for trace level quantification of uric acid in human urine.