1. Finding a perfect match of ion-exchanger and plasticizer for ion-selective sensors.
- Author
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Stelmach, Emilia, Wagner, Barbara, Maksymiuk, Krzysztof, and Michalska, Agata
- Subjects
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PLASTICIZERS , *CITRATES , *ION pairs , *DETECTORS , *VINYL chloride , *DETECTION limit - Abstract
Application of neutral ionophore based ion-selective sensors requires presence of ion-exchanger in the receptor phase, silently assuming that it is not only soluble but also dissociates to ions in the applied plasticizer. Although for typically applied ion-selective membrane constituents (plasticizers - ion-exchanger pairs) dissociation of ion-exchangers to ions is proven by theoretical (or close to) performance of resulting sensors, search for alternative plasticizers or ion-exchangers requires a method allowing estimation of the match of properties of involved compounds. In this work we propose a simple optical approach allowing estimation of ion-exchanger interactions with plasticizer. The results were confirmed by conductivity studies of model plasticizers solutions. The estimated dissociation constants of model ion-exchangers in plasticizers used are in excellent agreement with the results of optical studies. It was shown that solubility coupled with poor dissociation to ions of ion-exchanger affects performance of the resulting ion-selective membrane. Rational choice of properties of ion-exchanger and plasticizer allows finding a perfect match of the two, that results in improvements in performance of sensors (e.g. detection limits). As model sensors potassium and sodium ion-selective electrodes with poly(vinyl chloride) (PVC) based membranes, plasticized with classical plasticizer bis(2-ethylhexyl sebacate) or biodegradable alternative acetyl tributyl citrate, were prepared and studied using selected ion-exchangers. [Display omitted] • The effect of ion pair formation with the ion-selective receptor is studied with emphasis on sensor performance. • An optical approach allowing easy visualization of the dissociation of ion-exchanger in the plasticizer is proposed. • Ion pair formation between cation-exchanger and analyte cations affects performance of sensor. • The proposed optical approach can be helpful to predict suitability of ion-exchanger for the plasticizer. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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