RESUMO
Anelectrochemicallyreducedgrapheneoxide/goldnanoparticle-chitosan(ERGO/AuNP-CS) composite film modified glassy carbon electrode ( GCE) was constructed by directly electrochemical reduction of GO, and then assembly of AuNP-CS polycation on the surface. The surface morphologies of different modified electrodes including bare GCE, GCE/GO, GCE/ERGO and GCE/ERGO/AuNP-CS were characterized by scanning electron microscopy ( SEM ) . The differential pulse voltammetric behaviors of the electrodes were investigated, and the results indicated that the composite of ERGO/AuNP-CS exhibited excellent electrocatalytic oxidation activity to uric acid ( UA) molecule. In 0. 10 mol/L of phosphate buffer solution (pH=6. 5) with a scanning rate of 100 mV/s, the proposed composite film modified electrode showed a linear electrochemical response to UA in the range of 0 . 05-110 μmol/L with a detection limit of 12. 4 nmol/L ( S/N = 3 ). The electrode displayed good selectivity, reproducibility and stability in the determination of UA in human serum and urine samples with a recovery of 93 . 8%-104 . 1%. The detection results were agreed with those of conventional spectrophotometry and uricase Kit methods.
