Glassy carbon electrode modified with gold nanoparticles and DNA for the simultaneous determination of uric acid and norepinephrine under coexistence of ascorbic acid.

A novel biochemical sensor was assembled on a glass carbon electrode by a electrodeposition process. Gold nanoparticles were deposited by potential +1.5 V on the glass carbon electrode. CT-DNA was deposited by potential +1.5 V on the gold nanoparticles array electrode. The properties of the modified electrode were characterized by electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Our results showed that gold nanoparticles increase the DNA membrane capacitance and reduce the membrane resistance. This modified electrode can selectively determine uric acid and norepinephrine in the presence of a larger amount of ascorbic acid. The fabricated electrode showed good sensitivity, reproducibility, and stability.