Simultaneous electrochemical detection of Cu, Cd and Mn by nickel ferrite–cobalt ferrite bimetallic nanocomposite

The current study focuses on the synthesis of nanomaterials for fabrication of electrochemical sensors for the simultaneous detection of toxic metals, such as Cd, Cu, and Mn. Nickel and cobalt ferrite nanoparticles were synthesized by the sol-gel method and then combined by the green method to obtain a nickel ferrite-cobalt ferrite nanocomposite (NiFe₂O₄·CoFe₂O₄-NC) for electrochemical sensing of Cd, Cu and Mn. The characterization of the synthesized NiFe₂O₄·CoFe₂O₄-NC confirmed its coral-like shape with a highly rough and porous structure, cubic-spinel phase, crystalline size (<23.1 nm), good stability and electronic properties. NiFe₂O₄.CoFe₂O₄-NC/GCE was fabricated and showed good sensitivity due to its large electroactive surface area, fast electron transfer rate, and powerful electrocatalytic activity, which were beneficial for the quantitative determination of Cd, Cu and Mn. The NiFe₂O₄·CoFe₂O₄-NC/GCE showed the limit of detection of 0.083, 0.188 and 0.026 µg L^-1 for Cd, Cu and Mn, respectively. The proposed sensor was successfully applied for the analysis of Cd, Cu and Mn in tap water, mango juice, and milk samples, which confirmed its excellent efficiency with RSD < 4.0%.