Abdel‑Raoof, Ahmed MFouad, Manal M. Rashed, Noha SHosameldin, Asmaa IElgazzar, Elsayed 2023-07-242023-07-242023-06http://repository.msa.edu.eg/xmlui/handle/123456789/5640A new method for chlorthalidone (CLT) determination was developed on multiwalled carbon nanotube-modifed nanocrystal- line zinc chromite carbon paste electrodes (ZnCr2O4@MWCNTs/CPEs). Electrochemical performance of CLT was assessed by a cyclic voltammetry (CV) and diferential 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 par- ticles were identifed 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 afected by CNTs replacement. The EDX spectra afrm 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 modifed electrode exhibited improved activity and great conductivity in comparison with the bare sensor without modifcation. 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 efectively accurate and selective for the determination of CLT in tablet and biological fuids. This novel sensor was considered as environmentally friendly assisted by Eco-scale approach.en-USChlorthalidone ·Spinel-structured ZnCr2O4 ·Multiwalled carbon nanotubes ·Green assessment ·Diferential pulse voltammetryArticlehttps://doi.org/10.1007/s13738-023-02843-5