Cobalt Single-Atom Nanoparticles Anchored Graphene Oxide Electrode for Ultra-Sensitive Simultaneous Detection of Pb²⁺ and Cd²⁺ Using Square Wave Anodic Stripping Voltammetry

Despite legal restrictions on the industrial usage of toxic heavy metals, lead and cadmium remain among the major global water and environmental contaminants, posing significant risks to human health. Electrochemical sensors have emerged as efficient, sensitive, and cost-effective techniques for detecting heavy metals. This work explores the synthesis and application of cobalt nanoparticles (Co) and graphene oxide (GO) as electrocatalysts for the electrochemical detection of Cd2+ and Pb2+ ions. The synthesised materials were characterised using various surface morphological, structural, and electroanalytical techniques. The Co-GO-modified glassy carbon electrode (GCE/Co-GO) exhibited excellent electrocatalytic properties, including high surface area, conductivity, and stability. The glassy carbon electrode was utilised for individual and simultaneous detection of Cd2+ and Pb2+ ions using square wave anodic stripping voltammetry. GCE/Co-GO exhibited excellent performance, achieving detection limits as low as 0.610 nM for Cd2+ and 0.481 nM for Pb2+, which are well below the permissible levels and have potential for real-world applications. This study noted an interesting phenomenon of mutual interference, despite the wide detection peak range between the two metal ions studied.