voltammetric determination of ascorbic acid with zinc oxide modified glassy carbon electrode

Zinc oxide (zno) nanostructures electrodeposited from aqueous zinc nitrate solution at 70 °c onto glassy carbon electrode (gce) were used as electrochemical detectors. the morphology, structure, chemical composition and conductivity of the as-deposited layers were determined using scanning electron microscopy, x-ray diffraction, energy-dispersive x-ray analysis and uv–vis spectroscopy. a highly oriented crystalline zno deposit made of a dense array of randomly oriented hexagonal nanorods was obtained without any additives in solution. the electrocatalytic oxidation of ascorbic acid (aa) was studied using cyclic voltammetry in 0.1 m phosphate buffer solution at ph 6.8. comparing the response for aa oxidation on the bare and modified electrodes, the peak potential was shifted to − 0.45 v on zno/gce with higher current densities and transfer coefficient, due to a simultaneous increase in oxidation rate and surface area. a linear relationship was determined between the anodic peak current and the aa concentration in the range of 0.1–5 mm.