Highly selective simultaneous electrochemical detection of trace level of heavy metals in water samples based on the single-crystalline Co₃O₄ nanocubes modified electrode

This study discussed the simultaneous electrochemical detection of highly toxic Pb²⁺, Cu²⁺, Hg²⁺ heavy metals by the Co₃O₄ modified electrode. The Co₃O₄ nanocubes (Co₃O₄-NC) are prepared by the facile hydrothermal synthesis route which produces highly crystalline particles without an annealing process. The structural properties are characterized by XRD, Raman, XPS, FESEM, and HRTEM analysis. The SAED pattern endorses the single-crystalline nature of Co₃O₄-NC. The prepared material was subjected to detect the heavy metals electrochemically via DPV techniques. The Co₃O₄-NC/SPCE revealed good electroanalytical activity towards both individual and simultaneous detection of heavy metals. The developed heavy metal sensor exhibited good sensitivity (16.73 ± 0.8 µA µM⁻¹ cm⁻² for Pb²⁺, 11.46 ± 0.5 µA µM⁻¹ cm⁻² for Cu²⁺, and 16.86 ± 0.7 µA µM⁻¹ cm⁻² for Hg²⁺) and LOD (4.1 ± 0.2, 0.9 ± 0.04, 0.1 ± 0.005 nM for Pb²⁺, Cu²⁺, Hg²⁺, respectively) in the simultaneous detection. Moreover, the Co₃O₄-NC/SPCE exhibited high selectivity with the other potential interfering metal ions and nitro compounds in tap water and pond water samples. Additionally, the Co₃O₄-NC/SPCE reveals good recoveries of about 100–101.5% for tap water and 97–101% for pond water samples. Hence, our proposed Co₃O₄-NC/SPCE is a good electrode material for the determination of toxic heavy metal pollutants in real-time monitoring sensor devices.