VOLTAMETRIC DETERMINATION OF Cu IN FUEL USING CHEMICALLY MODIFIED ELECTRODE BY TETRAZOLES

This article describes an analytical procedure for the determination of copper in fuel samples using the modified graphite electrode basal pyrolysis (BPPGME) by tetrazolium salts: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2Htetrazolium (MTT) Br]. The determination of metals in fuel is an issue of environmental relevance because it believes that these elements can be released into the atmosphere causing damage to the environment and health. Fuel samples (ethanol, biodiesel and gasoline) were previously digested in a microwave oven using nitric acid and peroxides (biodiesel) and only nitric acid (alcohol and gasoline). The metal ion studied reacted on the surface of the chemically modified electrode to produce marked changes in the corresponding voltammograms. In order to determine the species of interest the best results were at pH 5.0 for copper and pH 6.0 for other species. The concentration scale for copper was 2.0x10-6 at 1.25 X 10-5 mol L-1. The limit of detection in fuels of samples (ethanol, biodiesel or gasoline), by ARV was 2.5x10-6 mol L-1. The accuracy of the proposed technique was compared by providing similar results, ie the copper concentration in the samples analyzed by both techniques at a non-statistically different 95% certainty level.