A high-sensitivity potentiometric iodide sensor was fabricated using tricaprylylmethylammonium chloride (TCMACl) as an ion exchanger incorporated into a PVC matrix. The constructed electrode demonstrated high performance characteristics toward I− ion, with a Nernstian slope of −59.2 ± 0.17 mV/decade, a wide dynamic working range extending from 5 × 10−7 to 5 × 10−2 M, and a low detection limit of 5.0 × 10−7 M. The proposed electrode was characterized by its fast response time of 4 s toward the analyte during calibration and the evaluation of iodide in samples. The surface of the prepared membrane was examined using SEM-EDX analysis, supported by mapping, and the stability of TCMACl in the membrane was studied using a mass loss method. The responsive sensor successfully determined the iodide concentration in antiseptic pharmaceutical drugs, achieving an average recovery of 96 % with a relative standard deviation (RSD) of 1.81 %. Additionally, the constructed sensor was applied as an indicator electrode in the potentiometric titration of AgNO3 against KI solution.