Review—Trends on the Development of Non-Enzymatic Electrochemical Sensors Modified with Metal-Oxide Nanostructures for the Quantification of Uric Acid

Uric acid is one of the most important metabolites as its blood levels can help to diagnose important diseases. Tradicionally, uric acid is determined by enzymatic-spectrophotometric techniques, but in recent years new promising alternatives have arisen. This review is devoted to the development over the past decade of non-enzymatic electrochemical studies based on nano-structures of non-noble metal oxides (Fe 2 O 3 , CuO, Cu 2 O, ZnO, NiO, MnO 2 , CeO 2 , MgO, SnO 2 and Co 3 O 4 ) for uric acid detection. The proposals showed the application of electrochemical sensors for the determination of uric acid in blood, urine, pharmaceuticals, water, and commercial shellfish. The developed electrodes are based on vitreous carbon electrodes, carbon paste, or screen-printed, mainly modified with nano-structures of metal oxides to electrochemically oxidize uric acid, where the anodic current peak is used as the analytical signal and the results reported are very promising.