Abstract: A novel Fe3O4 nanoparticles modified glassy carbon electrode(Fe3O4-np/GC electrode) was fabricated via a dropwise-coating method. The XRD pattern indicated that the Fe3O4 nanoparticles have pure cubic phase spinel structure, and the TEM image showed that the Fe3O4 nanoparticles are tiny spherical particles with mean size of 15~20 nm. The microstructure and electrochemical behavior of the modified electrode were investigated by scanning electron microscope(SEM) and electrochemical impedance spectrum(EIS). The electrochemical behaviors and kinetic parameters of cefotaxime sodium(CS) on Fe3O4-np/GC electrode were investigated by cyclic voltammetry(CV) and differential pulse voltammetry(DPV). The experimental results showed that the reduction peak current of CS increased significantly at modified electrode in comparison with that at GC electrode. In B-R buffer solution, the reduction peak currents are proportional to the concentrations of CS over the range from 7.0×10-8 to 1×10-6 and 1×10-6 to 4.5×10-5 mol/L, respectively, and the limit of detection is 5.0×10-8 mol/L. This method was applied in the determination of CS in four kinds of commercial injection samples and the recovery varies from 96.6% to 102.7%.

Key words: Modified electrode, Fe3O4 nanoparticle, cefotaxime sodium, electrocatalysis