Electrochemical behaviour of dimethyl-2-oxoglutarate on glassy carbon electrode

The electrochemical behaviour of dimethyl-2-oxoglutarate (MOG), a key intermediate in the Krebs cycle and an important nitrogen transporter in the metabolic pathways in biological processes, was investigated by cyclic voltammetry, square wave voltammetry and differential pulse voltammetry using a glassy carbon electrode. The reduction of MOG is an irreversible diffusion-controlled process that occurs in a cascade mechanism. For electrolytes with pH <3.0 and pH >7.0 one peak occurred and for 3.0<pH<8.0 two peaks corresponding to consecutive charge transfer reactions were observed. The effects of scan rate, concentration and pH of the electrolyte solution were monitored, and both peaks were found to shift cathodically with the increase in pH. DPV measurements allowed the determination of the number of electrons and protons i.e., one electron and one proton, involved in the reduction mechanism of MOG. Based upon the results obtained a reduction mechanism was proposed and the observed waves were attributed to the hydroxylation of the keto group of MOG to form dimethyl-2-hydroxyglutarate. Furthermore, two methodologies for the electroanalytical determination of MOG were also compared. (c) 2009 Elsevier B.V. All rights reserved.