SYNTHESIS, CHARACTERIZATION, AND APPLICATION OF A MAGNETIC NANOSTRUCTURED COFE₂O₃-BASED ELECTRODE PLATFORM FOR THE ELECTROCHEMICAL QUANTIFICATION OF ZINC

This work describes the development of an innovative electrochemical platform based on the magnetic nanostructured material CoFe₂O₃, aimed at the sensing of zinc. The platform was designed to be simple, fast, cost-effective, and with low waste generation, using drop coating of the glassy carbon substrate with a suspension of CoFe₂O₃ and Nafion®. The material was characterized using advanced techniques, including X-ray diffraction, infrared spectroscopy, transmission electron microscopy, electrochemical impedance spectroscopy, and thermogravimetry. These techniques confirmed the structural and functional properties of the material, suitable for the proposed application [1-3]. The resulting sensor exhibited remarkable electrochemical performance, with high-intensity and well-defined signals, and a quasi-reversible behavior in the ferri/ferrocyanide redox probe. The best results were obtained using Britton-Robinson buffer 0.10 mol L⁻¹ at pH 7.0, in combination with Square Wave Voltammetry. Optimization of the parameters allowed the analysis of the zinc redox process, which involves the transfer of two electrons as determined by the Tafel equation. The equation of calibration curve is represented by I_SW(μA) = -0.04336 + 0.0491[Zn²⁺]. The limits of detection and quantification were 0.51 μg L⁻¹ and 1.54 μg L⁻¹, respectively.