Determination of Cystein in biology solids by electrochemical methods with gold colloidal particles

The electrochemical behavior of cysteine at a graphite electrodes modified with gold nanoparticles was studied by cyclic voltammetry. We compared the results of determination of cysteine in the particulate, graphite and glasgraphite electrodes modified with gold nanoparticles and single crystals of gold. Specific feature of the electrooxidation of cystein at a graphite electrodes modified with gold nanoparticles and at a graphite electrodes modified from solution HAuCl₄. It was found that graphite electrodes modified with gold nanoparticles have more electrocatalytic activity toward the oxidation of cysteine than single crystals of gold due to the increase in the number of atoms on the surface of the graphite electrode in comparison with single crystals of gold, which catalyze the oxidation process of cystein. The use of graphite electrode modified with gold nanoparticles reduces the detection limit for cystein under to 1. 10^-12 M. The method for determination of cysteine in biological samples.