Electrochemical application of ZnCr2O4@MWCNTs‑modifed carbon paste electrode for sensing of chlorthalidone in its biological fuids

Abstract

A new method for chlorthalidone (CLT) determination was developed on multiwalled carbon nanotube-modified nanocrystalline zinc chromite carbon paste electrodes (ZnCr2O4@MWCNTs/CPEs). Electrochemical performance of CLT was assessed by a cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The nanostructures ZnO, ZnCr2O4, and ZnCr2O4/MWCNTs were prepared by chemical co-precipitation method. The microstructural, composition, and mean size of the particles were identified using XRD, EDX, and TEM techniques. ZnO showed a well crystallinity of crystal size 32 nm, while the spinel ZnCr2O4 exhibited a small particle size of approximately 10 nm. ZnCr2O4/MWCNTs showed poor crystal structure affected by CNTs replacement. The EDX spectra affirm the presence of the elements Zn, Cr, O, and C into the nanocomposite lattice, and the TEM micrographs indicated the particles in hexagonal and spherical shapes with a small size. The modified electrode exhibited improved activity and great conductivity in comparison with the bare sensor without modification. The method was linear from 0.1–9 μmol L−1 with a minimum detection limit of 0.03 μmol L−1. Lastly, the proposed procedure was effectively accurate and selective for the determination of CLT in tablet and biological fluids. This novel sensor was considered as environmentally friendly assisted by Eco-scale approach.