Introducing a Polymeric Ion Exchanger as a Modifier for Carbon-Paste Potentiometric Sensors

Abstract

Development in polymer chemistry empowers creative analytical solutions. Polymers have provided a multitude of separation modes in solid-phase-extraction and chromatography, also they served as matrices for chemical sensors. The current study introduces a polymeric cation-exchanger as a modifier for a solid-state Zn(II) sensor. Literature relates the deteriorated response and limited performance of potentiometric-sensors to the leaching of ion-exchanger and/or analyte out of the sensor matrix. The polymer’s limited solubility, small particle size, large surface area, and strong ion-exchanging capacity counteract the efflux of the sensor ingredients, thereby, enhance its performance. An initial optimization study included seven different sensors to reach optimal sensor composition. The optimized sensor maintained a Nernstian response over two months with a slope of 28.06 ± 0.05 mV decade−1, a linear range of 6.3 × 10−6−1 × 10−2 M, and a detection limit of 5.12 × 10−6 M within pH range 4.3–6.8. Statistical comparison shows no significant difference from the official method. Sensor performance parameters were further compared with those of the reported Zn(II) sensors to highlight the advantages and limitations of polymeric ion-exchanger. The sensor expressed a relatively lower detection limit and faster response time. Polymeric exchangers provide potential opportunities to enhance potentiometric sensor performance.