Comparative Study of Carbon Paste, Screen Printed, and PVC Potentiometric Sensors Based on Copper‐sulphamethazine Schiff Base Complex for Determination of Iodide – Experimental and Theoretical Approaches

New poly vinyl chloride (PVC) membrane, carbon paste (CP), and screen printed (SP) electrodes are constructed for iodide sensing. They are based on copper (II)‐sulphamethazine Schiff base complex as suitable carrier. Mechanism was proved by FT‐IR and UV‐Vis spectroscopy. Computational study involving binding energies calculations at DFT/B3LYP level of theory confirmed the proposed mechanism and agreed the observed selectivity pattern. Responses are near‐Nernstian (−55.0, −51.0 mV/concentration decade) for PVC, and SP electrodes, and super‐Nernstian (−61.2 mV/concentration decade) for the CP electrode. Lower limit of detection (3.2×10−6 mol L−1) and improved selectivity over the highly interfering thiocyanate were obtained in comparison with the previously reported Schiff base complexes‐based iodide sensors.