Electrochemical determination of glutathione in hemolyzed erythrocytes

The physiological significance of determining glutathione (GSH) and its oxide form is obvious from their applications in clinical practices such as diagnostic experiments for diabetes, Parkinson’s disease, and cancers. Such an important detemination still needs the development of certain experimental procedures that are easy, fast, and cheap enough to implement. These procedural advantages can be provided through electrochemical methods. Therefore, in this study, at the surface of a glassy carbon electrode (GCE), a composite of functionalized multi-walled carbon nanotubes (MWCNTs) and formazon was used as a mediator to determine GSH electrochemically. The results indicated that this modified GCE is electrocatalytically very active for glutathione oxidation. Several techniques including cyclic voltammetry (CV), scanning electron microscopy (SEM), and differential pulse voltammetry (DPV) were used to characterize the electrode. Also, such kinetic parameters as the charge transfer rate constant and the transfer coefficient were calculated. In optimized conditions, there was a linear relationship between the DPV peak current of GSH oxidation and GSH concentration in the ranges of 1.0-100.0 and 100.0-800.0 µM at pH 7.0. As for the detection limit, it was found to be 0.73 µM.