Development of electrochemical sensor based on magnetite nanoparticles for determination of dopamine

In this thesis study, for the determination of dopamine, electrochemical sensor based on magnetite (Fe3O4) nanoparticles was developed. For this, firstly, Fe3O4 nanoparticles modified carbon paste was prepared by mixing Fe3O4 nanoparticles, graphite powder and mineral oil as binding, A portion of the given pastes was placed firmly into a cavity of polyetheretherketone rod electrode bodies and proposed electrodes were named as Fe3O4-MCPE. Electrochemical characterization of Fe3O4-MCPEs was studied via electrochemical impedance spectroscopy and cyclic voltammetry. The obtained results were compared with those obtained by unmodified carbon paste electrode (BCPE) and electrocatalytic efficiency of Fe3O4 nanoparticles was proved. Besides, optimum paste composition was determined and the optimum Fe3O4 nanoparticles / graphite powder ratio was found as 1/6. The electrochemical oxidation behavior of dopamine was studied by using both electrodes and compared to BCPE, at Fe3O4-MCPE, the oxidation potential was shifted toward more negative potential and the oxidation current was increased remarkably. Also linear working range and limit of detection were determined as 1.0×10-6 M ̶ 1.0×10-4 M and 1,9 ×10-7 M, respectively. The analytical application of proposed sensor was evaluated by determination of recovery values of dopamine in dopamine injection solution. The values of recovery (%) were calculated as 97.4 – 101.7. Key Words: Dopamine, Magnetite nanoparticles, electrochemistry, sensor, carbon paste electrode