Computational and Electrochemical Studies on the Redox Reaction of Dopamine in Aqueous Solution

The electrochemical behavior of dopamine, an important biological molecule, was investigated by means of cyclic voltammetry (CV) at various potential scan rates. All experiments were done in aqueous phosphate buffer solutions at different pHs. The experimental formal redox potential (Eo’) of dopamine was obtained to be 752 mV versus SHE (Standard Hydrogen Electrode). Eo’ values have also been calculated with the aid of density functional theory (DFT) method at B3LYP/6-311++G** 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 dopamine in the order of 782 and 710 mV, respectively. These results were found to be in excellent agreement with the experimental value in the order of 752 mV. Furthermore, Ultraviolet-visible (UVvis) spectrum was evaluated by Time Dependent DFT (TD-DFT). Based on this study, characteristics of the electronic absorption spectrum in the visible and UV regions were assigned to π→π* transitions.