Synthesis and Characterization of Doped Metal Oxide/Graphene Oxide Nanocomposites for Electrochemical Sensing of Neurotransmitters

Abstract

Dopamine is one of the main neurotransmitter of our body. The alteration in the normal concentration give rise to the multiple disorder and diseases. The electrochemical measurements of dopamine with bare electrode is not possible due to various problem like electrochemical fouling, interference species have same oxidation potential and lower concentration of dopamine in biological samples. The modification of working electrode is essential for fast, accurate, selective and sensitive detection of dopamine. Metal oxide/graphene oxide nanocomposites have attracted great attention due to the synergistic effect. Zinc and cobalt nanoparticles contain several properties such as catalytic activity, high surface area, electrochemical activity, and oxygen transferability which are attractive for sensor applications. In this project the main objective is to study the synthesis, characterization and application of a new hybrid material designated as doped metal oxide/graphene oxide. In this work doped metal oxide/graphene oxide nanocomposites has been synthesized by hydrothermal and co-precipitation route. Modification of the glassy carbon electrode (GCE) surface has been by the synthesized nanocomposite. For the detection of neurotransmitters (dopamine) these modified GCE/ZnO/Co3O4 electrodes has been used. The electrochemical properties of the ZnO/Co3O4 modified electrode were investigated by the cyclic voltammetry and amperometric current-time method. The modified electrode has shown high electrochemical activity for the catalytic reduction and detection of dopamine. The nonenzymatic dopamine sensor shows wide linear range of 2- 90 mM (R = 0.97). The hybrid nanocomposite has exhibit the low limit of detection (LOD) 0.26 µmol L-1 , limit of quantification (LOQ) 0.813 µmol L-1 and sensitivity 1.32 µA. µmol L-1 were found.