Use of electrodes modified with carbon nanotubes for the analysis of thiols in samples of biological interest

Abstract

Thiol groups play a crucial role in maintaining biological systems. This groups can be oxidized producing disulfur bridges. Cysteine (aminoacid) and glutathione (peptide) are examples of biomolecules that have thiol groups. Different methods have been reported for the determination of biomolecules with thiol groups, among them, electrochemical methods. The electrochemical oxidation of these molecules using conventional electrodes presents low kinetics and this leads to low sensitivities. Screen-printed electrodes (SPE) are a kind of electrodes that present low cost and simplicity of operation, but they also present a low sensitivity for the determination of thiols. In order to increase this sensitivity, a modification of the screen-printed carbon electrodes with carbon nanotubes has been studied, due to due to the fact that the electrocatalytic activity of these nanoparticles is able to accelerate the oxidation of thiol groups...