Determination of the absolute redox potential of methyldopa: experimental and simulation methodes

The conditional formal potential, E°′of Methyldopa has been studied by cyclic voltammetry at the surface of activated glassy carbon electrode (AGCE) as the working electrode in different pH phosphate buffered solutions. The experimental Standard redox potential, E°′, of Methyldopa is obtained to be 0.72 mV versus SHE (Standard Hydrogen Electrode). E°′ values have also been calculated with the aid of density functional theory (DFT) method at B3LYP/6-311G Basis set in conjunction with a Polarizable Continuum Model (PCM). Innovative application of both Direct and indirect methods resulted in theoretical standard electrode potentials of the studied Methyldopa in the order of 0.68 and 0.74 mV, respectively. These results were found to be in excellent agreement with the experimental value in the order of 0.72 mV.