Impedimetric pyrene determination at fMWCNTs/CuO-ZnO modified glassy carbon electrode

Abstract Pyrene, a well-known polycyclic aromatic hydrocarbon and persistent environmental pollutant, poses significant health and environmental risks due to its high potential for toxicity and carcinogenicity. An electrochemical impedimetric nanosensor has herein been developed to facilitate its rapid and sensitive detection. The sensor, designated as GCE/fMWCNTs/CuO-ZnO, comprises a glassy carbon electrode (GCE) modified with a nanocomposite of copper oxide-zinc oxide (CuO-ZnO) and functionalized multi-walled carbon nanotubes (fMWCNTs). The nanomaterials were synthesized, and an array of analytical techniques comprising Fourier transform infrared spectroscopy, energy dispersive X-ray spectroscopy, X-ray powder diffraction (XRD) spectroscopy, and transmission electron microscopy were used for their characterization. The surface of the glassy carbon electrode (GCE) was coated with the nanomaterials, and their electrochemical properties were probed using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry. The electrochemical behaviour of pyrene investigated on the GCE/fMWCNTs/CuO-ZnO sensor revealed impedance responses at varying pyrene concentrations, demonstrating high sensitivity at a detection limit of 52.85 nM. The transfer of electrons at the surface of the electrochemical sensor was facilitated by the highly conductive and electrical nature of the functionalized multi-walled carbon nanotubes (fMWCNTs), which enhanced the catalytic properties of the CuO-ZnO nanostructure. The combination of electrochemical impedance spectroscopy (EIS) with the synergy between the functionalized MWCNTs and CuO-ZnO nanocomposite resulted in an improved potential for pyrene determination. The proposed sensing platform therefore presents a promising tool for pyrene detection. Graphical abstract