Electrocatalytic oxidation and determination of dexamethasone at an Fe3O4/PANI–CuII microsphere modified carbon ionic liquid electrode

Abstract

A novel, simple, sensitive and selective electrochemical sensor based on an Fe₃O₄/PANI–Cu^II microsphere modified carbon ionic liquid electrode is constructed and utilized for the determination of dexamethasone. The synthesized Fe₃O₄/PANI–Cu^II microspheres are characterized by routine methods such as X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), thermo gravimetric analysis (TGA), and inductively coupled plasma atomic emission spectroscopy (ICP-AES). The Fe₃O₄/PANI–Cu^II microspheres can significantly accelerate the electron transfer rate and represent excellent synergistic electrochemical activity for the oxidation of dexamethasone. Differential pulse voltammetry (DPV) was used for the quantitative determination of dexamethasone. As shown, the oxidation peak current is linear with the concentration of dexamethasone in the range of 0.05 to 30 μM with a detection limit of 3.0 nM which is more sensitive than most of the previously reported methods. The proposed method is successfully applied to the sensitive determination of dexamethasone in real samples with satisfactory recoveries.