Fabrication of poly(1H-imidazole-4-carboxylic acid)-zinc oxide nanoparticle modified glassy carbon electrode and its application for simultaneous determination of ascorbic acid, dopamine and uric acid

A poly 1H-imidazole-4-carboxylic acid(PHIMC)modified glassy carbon electrode(GCE)pre-coated with zinc oxide (ZnO)nanoparticle(PHIMC-ZnO/GCE)had been fabricated and used for simultaneous detection of ascorbic acid(AA), dopamine(DA) and uric acid (UA). The surface morphology and electrochemical activity of the modified electrode were investigated by scanning electron microscopy(SEM)and electrochemical methods.The electrochemical behaviors of AA, DA and UA on the modified electrode were investigated by cyclic voltammetry(CV)and differential pulse voltammetry(DPV). The results show that modified electrode exhibits strong electro-catalytic activities toward oxidations of AA, DA and UA in a PBS buffer solution(pH=7.0).Under the optimum conditions, the linear concentration dependences of DPV current responses were observed for AA, DA and UA in the molar concentration ranges of 80-1 400, 0.15-45.00 and 2-120 μmol·L-1. The detection limits(S/N=3)of AA, DA and UA are 0.50, 0.03 and 0.09 μmol·L-1, respectively. And also, the different electrochemical behaviors of AA, DA and UA at PHIMC-ZnO/GCE under various scan rates indicate that the electrode reaction of AA, DA and UA is an adsorption-controlled process.The PHIMC-ZnO/GCE has been applied for the simultaneous determination of AA, DA and UA in human urine and serum samples with satisfactory results