Anthracene electrochemical sensor at fMWCNTs/ZnO modified glassy carbon electrode
Funmilola A. Adesanya, Omolola E. Fayemi
Abstract
The development of efficient and sensitive methods for polycyclic aromatic hydrocarbon (PAH) determination is necessitated by their potential environmental and health hazards. This study explores the application of glassy carbon electrode (GCE) modified with a nanocomposite of zinc oxide nanoparticles (ZnO NPs) reinforced functionalized multi-walled carbon nanotubes (fMWCNTs) as electrochemical sensor in the determination of anthracene. The functional, structural, and morphological properties of the nanomaterials were examined using techniques such as X-ray powder diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which validated the authenticity of the synthesis. Fabrication of the glassy carbon electrode was done utilizing the drop-coating method and the electrochemical properties probed in 10 mM [Fe(CN)6]3-/4- redox probe via electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The nanocomposite-modified electrode, GCE/fMWCNTs/ZnO NPs recorded the highest anodic current response in the redox probe towering well above the other electrodes - bare GCE, GCE/ZnO NPs and GCE/fMWCNTs. The synergy between ZnO NPs and the fMWCNTs suggests accelerated transport of electrons between the ferrocyanide - ferricyanide redox probe and the modified electrode. Thereafter, the nanocomposite was explored for anthracene determination using CV and square wave voltammetry. With a similar performance in 0.4 μM anthracene, the GCE/fMWCNTs/ZnO NPs generated a higher cyclic voltammetry anodic current response of (459.05 μA), in contrast to the other electrodes - GCE/fMWCNTs (288.82 μA) GCE/ZnO NPs (19.67 μA), and the bare GCE (16.41 μA) at a scan rate of 25 mV/s, revealing very good electrocatalytic activity. A linear correlation (over a range of 9 to 75 µM) between the anodic current response and anthracene concentration yielded a micromole limit of detection of 1.27 µM. The proposed electrode was successfully used for the quantitation of anthracene in wastewater.