Fabrication of CeO₂ Nanoparticle Modified Glassy Carbon Electrode for Ultrasensitive Determination of Trace Amounts of Uric Acid in Urine

The preparation of a glassy carbon electrode modified by CeO₂ nanoparticles was described, which was characterized by cyclic voltammetry and electrochemical impedance spectroscopy. In pH 6.0 buffer, the CeO₂ nanoparticle modified electrode (CeO₂ NP/GC) gave an excellent electrocatalytic activity for the oxidation of uric acid (UA). The catalytic current of UA versus its concentration had a good linear relation in the range of 2.0×10⁻⁷−5.0×10⁻⁴ mol/L, with the correlation coefficient of 0.9986 and detection limit of 1.0×10⁻⁷ mol/L. The modified electrode can be used for the determination of UA in urine, which can tolerate the interference of ascorbic acid up to 1000-fold. The method was simple, quick and sensitive.