Biosensor for Detecting Uric Acid in Urine

In this work, we developed a highly sensitive electrochemical enzyme electrode that directly determines the uric acid (UA) concentration in urine. Results from cyclic voltammetry testing showed a well-defined oxidation peak at 0.35 V, but no reduction peak, indicating that an irreversible redox reaction was executed. The enzyme electrode’s modification method was optimized as follows: 0.1% chitosan, 0.3% graphene oxide, 5 mmol L -1 uricase, and 25% glutaraldehyde. Under these optimal conditions, there was a good linear relationship between the redox peak current and UA concentration in the range of 0.1-2 mmol L -1 (I=4.1661 CUA + 2.0445; R 2 =0.9995); and the detection limit was 0.023 mmol L -1 (S/N = 3.3). The modified electrode showed high repeatability (RSD = 3.34%), good stability (12 days), and strong antiinterference capability. Therefore, this electrode can quickly and accurately determine the UA concentration in urine. This study is highly significant for monitoring UA levels in gout populations and preventing kidney damage caused by gout.