Modified Diamide and Phosphine Oxide Extracting Compounds as Membrane Components for Cross-Sensitive Chemical Sensors

Maria Khaydukova,Danila Militsyn,Dmitry Kirsanov,Vasily Babain,Mikhail Karnaukh,Andreas Wilden,Bohumir Grüner,Andrey Legin,Pavel Selucký

doi:10.3390/chemosensors7030041

Abstract

This research is devoted to the development and study of novel cross-sensitive sensors based on modified extracting ligands. According to the previous results of liquid extraction studies, the chemical modification of membrane active components would change the analytical characteristics of a sensor comprising them. The sensing elements of the studied sensors consisted of various derivatives of N,N,N′,N′-tetraoctyldiamide of diglycolic acid (TODGA) and di-phenyl-N,N-di-i-sobutylcarbamoylmethylen phoshine oxide (CMPO) used as neutral carriers, CCD (chlorinated cobalt dicarbollide) as a lipophilic additive, different plasticizers, and poly(vinyl chloride) (PVC) as a polymer. TODGA-based sensors demonstrated a stable and reproducible response towards rare earth cations in acidic media (pH = 2). Changing the concentrations and ratio of neutral carriers and the lipophilic additive, it is possible to modify the sensitivity and selectivity of the sensors towards the same target ions. Bonded ligands, such as cobalt dicarbollide covalently attached to TODGA and CMPO, exhibited lower selectivity and sensitivity to rare earth cations. A possibility to vary the cross-sensitivity patterns of the sensors in a wide range might be of great interest for the development of multisensor systems allowing the simultaneous determination of several analytes in multicomponent solutions.

Highlights

Potentiometric sensors are attractive analytical tools giving an opportunity to analyze liquids in a simple, fast, and non-destructive way with high sensitivity and reasonable accuracy
When chemically and physically similar analytes are simultaneously present in a sample solution, it is hardly possible to develop a highly selective sensor for each individual component
The main purpose of this work was to number of cross-sensitive with variable sensitivity and selectivity towardpatterns lanthanides

Summary

Introduction

Potentiometric sensors are attractive analytical tools giving an opportunity to analyze liquids in a simple, fast, and non-destructive way with high sensitivity and reasonable accuracy. Ion-selective electrodes (ISEs), being the most popular potentiometric sensors, are recommended for pH determination by several international standards (e.g., ISO 10523:2008(en)). Frequently observed non-Nernstian behavior and insufficient selectivity complicate the wider implementation of ISEs into analytical practice. A majority of existing sensors exhibit, to a different extent, a property of cross-sensitivity, being sensitive and selective to a target analyte, and to other components. When chemically and physically similar analytes are simultaneously present in a sample solution (e.g., rare earth elements), it is hardly possible to develop a highly selective sensor for each individual component.

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