Electrocatalytic Oxidation and Determination of Dopamine Concentrations Based on Fe3O4-Polyaniline Nanoparticles/Glutamic Acid Chemically Modified Electrodes

In order to detect dopamine (DA) with good selectivity and sensitivity based on the nanoparticles modified electrode, magnetic and conducting Fe3O4-polyaniline (Fe3O4-PANI) composite nanoparticles have been prepared. Fe3O4-PANI composite is composed of nanometer-sized particles (Fe3O4 about 30 nm and Fe3O4-PANI about 150 nm). It has been modified onto the glassy carbon electrode (GCE). Then, Fe3O4-PANI modified GCE has been used to adsorb the glutamic acid (Glu) in order to investigate the electrocatalytic oxidation and determination of DA by cyclic voltammetry (CV). A sharp couple of redox peaks were obtained, and a decrease of 160 mV in overpotential for DA oxidation at the modified GCE was observed. It was found that the modified electrode was able to determine the concentration of DA from 1 x 10(-8) to 5 x 10(-3) mol/L with the correlation coefficient of 0.9998, and the detection limit (S/N = 3) is 7.82 x 10(-9) mol/L. In addition, the present method was applied to the determination of DA with good selectivity and sensitivity in the sample with the co-existence ascorbic acid.