The mathematical description of dopamine electrochemical oxidation, accompanied by its chemical and electrochemical polymerization

Abstract

The electrooxidation of dopamine is accompanied by its chemical and electrochemical polymerization, and in which either the monomer or the polymer may be oxidized to the respective quinonic form, was investigated from the theoretical point of view. Dopamine is one of the important neurotransmitters in human and mammal organisms. It is a precursor to epinephrine, which influences the cardiovascular, hormonal and renal functions. Its lack causes diseases like Parkinson, therefore, dopamine has been used as a drug for their treatment. On the other hand, its excess stimulates the sympatic nervous system yielding the metabolic disorders and even schizophrenia. Thus, the development of the rapid and accurate method for its concentration measurement is very important. Dopamine is very popular analyte in electroanalytical systems. The modified electrodes for its determinations have been developed by many researchers. Dopamine is widely used as a monomer for synthesis of a conducting polymer – polydopamine, whis is used as electrodes’ modifier in capacitors and in anticorrosive coatings. The electropolymerization of dopamine into polydopamine proceeds along with its traditional quinone-hydroquinonic oxidation. Both processes give their impact to the electrochemical behavior of dopamine during its electropolymerization. The mechanism’s complexity is also responsible for the electrochemical instabilities during electro-oxidation. In order to understand these instabilities it’s necessary to develop the mathematical model that is capable to describe the behavior of the system. It also helps us to esteem the influence of the electrochemical instabilities, by which it may be accompanied. The goal of this work is to describe an electrochemical oxidation and polymerization of dopamine that will provide an important connection between the electrochemical detection of biologically active compounds and their electropolymerization for electrode modification.