Electrocatalytic oxidation and detection of N-acetylcysteine based on magnetite/reduced graphene oxide composite-modified glassy carbon electrode

Graphical abstract: The Fe3O4/RGO composite has been successfully synthesized by a facile one-pot in-situ procedure. With its high surface area and excellent electrocatalytic activity, the electrochemical sensor based on the composite-modified glassy carbon electrodes was fabricated and applied in detecting the process of NAC electrocatalytic oxidation. -- Highlights: • RGO/Fe3O4 composite was synthesized by a facile one-pot in-situ procedure. • The RGO/Fe3O4-modified GCE was used for electrocatalytic oxidation of NAC. • Kinetic performance and detection limit of oxidation process were investigated by using different electrochemical methods. -- Abstract: The magnetite/reduced graphene oxide (Fe3O4/RGO) composite was synthesized by a facile one-pot in-situ method and characterized by transmission electron microscopy, atomic force microscopy, vibrating sample magnetometer, X-ray powder diffraction, surface area and pore size distribution, thermogravimetric analysis, Raman spectroscopy and X-ray photoelectron spectroscopy, respectively. The composite consisted of the RGO substrate with a single-layered Fe3O4 nanoparticle film, which showed the large surface area of 352 m2 g−1 and the saturated magnetization of 26.7 emu g−1. The average diameter and coverage ratio of Fe3O4 were about 8 nm and 50%, respectively. The electrocatalytic oxidation and detection of N-acetylcysteine (NAC) based on composite-modified glassy carbon electrodes (GCE) were investigated by cyclic voltammetry, amperometry, double potential step chronoamperometry and differential pulse voltammetry. Especially, the kinetic performance of oxidation processes were estimated by the Cottrell equation, indicating the diffusion coefficient of 2.06 × 10−5 cm2 s−1 and the catalytic reaction rate constant of 3.47 × 106 cm3 mol−1 s−1. Compared with the kinetic parameters, it was found that the oxidation process included both slow absorption and quick diffusion processes. The detection limit of NAC was 1.11 × 10−5 mol L−1 in the range of 0.10–10.0 mmol L−1