Development of Chromium(III)-selective Potentiometric Sensor by Using Synthesized Pyrazole Derivative as an Ionophore in PVC Matrix and its Applications

Abstract

A novel poly(vinyl chloride) membrane potentiometric sensor for chromium(III) ions based on the use of 5,5′-(1,4-phenylene)bis(3-(naphthalen-1-yl)-4,5-dihydro-1H-pyrazole-1-carbothioamide) as a neutral ionophore was developed. The optimum composition of the best performing membrane contained ionophore, potassium tetrakis (p-chlorophenyl) borate (KTpClPB), dibutyl phthalate (DBP), and poly(vinyl chloride) (PVC) in the ratio of 5.5:1.5:55:38 (mg). The sensor exhibits a working concentration range of 1.0 × 10–5–1.0 × 10–1 mol L−1 and a detection limit of 1.7 × 10–6 mol L−1. The sensor shows good selectivity for chromium(III) ions over a number of cations including alkali, alkaline earth, heavy and transition metals. The response time of the sensor is 8 s. In addition, the developed sensor shows good reusability and stability. The sensor operates in the wide pH range of 5.0–11.0. The sensor could be used as an indicator electrode in the quantification of Cr3+ ions by potentiometric titration against ethylenediaminetetraacetic acid (EDTA). Finally, this sensor was successfully used for the determination of chromium(III) in commercial water, purification water and wastewater.