Vol. 7, Issue 10, Part A (2025)

The imine-quinoline derivative ligand, namely (Z)-3-(((2-((2-aminophenyl) thio) phenyl) imino) methyl)-7-chloronaphthalen-2-ol, was synthesized and employed as an ionophore in the fabrication of poly (vinyl chloride) (PVC)-based membrane electrodes selective for Cu (II) ions. Optimal electrode performance was achieved with a membrane formulation consisting of (L): PVC: NaTPB: NPOE in the ratio 5:120:3: 150.The developed sensor exhibited excellent selectivity and sensitivity towards Cu (II) ions over a wide range of competing cations, including alkali, alkaline earth, transition, and heavy metal ions. The effects of membrane composition, solution pH, and the presence of anionic additives on the potentiometric response were systematically examined. The electrode demonstrated near-Nernstian behaviour with a slope of 29.6 mV decade⁻¹ over a broad concentration range of 5.0 × 10⁻⁷ to 1.0 × 10⁻¹ mol L⁻¹, with a detection limit of 3.0 × 10⁻⁷ mol L⁻¹. The sensor provided rapid response times (<15 s) throughout the tested concentration range and maintained stable performance for up to 12 weeks within a pH range of 2.8-5.8. The proposed electrode was successfully applied for the determination of Cu (II) in various water samples and served effectively as an indicator electrode in the potentiometric titration of Cu (II) ions with EDTA.