Electrochemical Detection of As(III) by a rGO/Fe₃O₄-modified Screen-Printed Carbon Electrode

A reduced graphene oxide (rGO)/Fe₃O₄ composites modified screen-printed carbon electrode (SPCE) was used to determinate As(III) in a HAc-NaAc buffer solution. The rGO/Fe₃O₄ composites were prepared by a simple and one-pot synthesis method, and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), FT-IR and Raman spectra. The electrochemical behaviors of the composite electrode were characterized by cycle voltammetry and electrochemical impedance spectroscopy. The experimental parameters, such as supporting electrolyte, solution pH, deposition potential, deposition time were optimized, respectively. The calibration curve for the detection of As(III) in the range of 2 to 20 ppb was I = -4.495 + 1.922C, with a coefficient of 0.994. The sensitivity was 1.922 μA/ppb, and with about twice Fe₃O₄ modified SPCE, a detection limit as low as 0.3 ppb was achieved. The proposed electrode was validated by analyzing the As(III) content in real water samples.