Zinc oxide nanoparticles modified-carbon paste electrode used for the electrochemical determination of Gallic acid

Zinc oxide nanoparticles (nano-ZnO) was used to modify carbon paste electrode (CPE) for a fast and sensitive electrochemical determination of gallic acid (GA). The study was carried out using cyclic voltammetry (CV and differential voltammetry (DPV) techniques, where the nano-ZnO-modified electrode exhibited an efficient and sensitive oxidation of GA. The cyclic voltammetric result showed a significant enhancement of the peak current from 250 mu A to about 410 mu A. The electrochemical behaviour of GA on the nano-ZnO modified carbon paste electrode was studied using DPV, showing a sensitivity of the electrode in a concentration range of 1 x 10(-6) to 5.0 x 10(-5) mol L-1, with a correlation coefficient R-2 of 0.9968 and a limit of detection of 1.86 x 10(-7) mol L-1 (S/N =3). The proposed electrode was used successfully for the determination of GA in red wine with recoveries of 103%.