A novel electrochemical sensor based on Co3O4-CeO2-ZnO multi metal oxide nanocomposite for simultaneous detection of nanomolar Pb2+ and Hg2+ in different kind of spices

Abstract

Simultaneous and individual determination of Pb²⁺ and Hg²⁺ ions were carried out based on the synergistic effect of Co₃O₄, CeO₂ and ZnO nanoparticles into the carbon paste electrode. The morphology of synthesized nanocomposite (Co₃O₄-CeO₂-ZnO) was investigated by Scanning Electron Microscope, Transmission Electron Microscope, X-ray diffraction and Fourier Transform Infrared spectroscopy. The voltammetric current has increased linearly by increasing the concentration of Pb²⁺ and Hg²⁺ ions. The linear ranges of the Co₃O₄-CeO₂-ZnO/CPE sensor were obtained 0.27-18.42 (for Pb²⁺ ions) and 0.42-31.30 nM (for Hg²⁺ ions), under optimum condition. The detection limits (3S_b/m) were obtained 0.054 nM for Pb²⁺ and 0.097 nM for Hg²⁺, respectively. The proposed electrochemical sensor acts as a sensitive and selective method for simultaneous determination of two heavy metal ions and shows excellent repeatability, reproducibility, and stability, with relative standard deviation (RSD) less than 3%. Finally, Co₃O₄-CeO₂-ZnO/CPE was successfully applied for the determination of Pb²⁺ and Hg²⁺ in different kind of spices.