Catalytic activity of gold for the electrochemical reduction of p-nitrophenol: analytical application

Para-nitrophenol (PNP) is a toxic compound that enters the environment during manufacturing and processing of a variety of industrial products. In this work, we present a study on the electrocatalytic reduction of PNP to p-hydroxyl aminophenol in aqueous solutions using metallic gold electrode. p-Hydroxyl aminophenol has been used abundantly as a model substance to check the catalytic activity of metallic gold electrode. Here, we present a full kinetic scheme that includes the intermediate p-Hydroxyl aminophenol. The discussion of the resulting kinetic equations shows that the reduction of PNP at the surface of metallic gold electrode is a diffusion transfer process and irreversible. The analytical performance was also evaluated with respect to PNP concentration, and other variables. A linear calibration graph was obtained in the concentration range from 5.0 x 10(-7) to 5.0 x 10(-3) mol L-1 PNP. The detection limit was found to be 5.0 x 10(-7) mol L-1. For eight tests, the differential pulse response was reproduced with 1.9% relative standard deviation at 5.0 x 10(-6) mol L-1 PNP in acetate buffer solution.