Abstract

In this work it was obtained a modified electrode by inclusion of the enzyme glutathione peroxidase (GPx) on a conductive polymer, polypyrrole (PPy), deposited on a graphite electrode (GC|PPy, GPx) for the amperometric detection of reduced glutathione (GSH) in presence of hydrogen peroxide. Also, working conditions were optimized in order to prepare the electrode GC|PPy, GPx, which were tested for different concentrations of monomer and enzyme, electrochemical type of perturbance (by fixed potential or cyclic voltammetry) deposition potential and time (PPy film thickness, GPx), etc. by testing the response of the electrodes versus GSH in presence of hydrogen peroxide at physiological pH and temperature. At optimal experimental conditions, the achieved electrode gives a characteristic response for the analyte, which means that this modified electrode can be proposed as a selective GSH sensor, since it was shown that the enzyme maintains its activity during experimental manipulations and responds in a highly reproducible mode, so its use is proposed as an amperometric biosensor which is highly selective and stable.