Supramolecular Chemistry Approach to the Design of a High-Resolution Sensor Array for Multianion Detection in Water

Abstract

Reliable sensing of structurally similar anions in water is a difficult problem, and analytical tests and sensor devices for reliable sensing of multiple anions are very rare. This study describes a method for fabrication of simple colorimetric array-based assays for aqueous anion solutions, including complex analytes encountered in real-life applications. On the fundamental level, this method shows how the discriminatory capacity of sensor arrays utilizing pattern recognition operating in multianalyte environments may be dramatically improved by employing two key features. The synergy between the sensor and hydrogel host resembles the cooperative effects of an apoenzyme and cofactor: the host hydrogel helps extract the target anions from the bulk analyte while stripping the solvate molecules off the anions. In addition, the supramolecular studies of the affinity and selectivity of the potential sensors for target analytes allow for constructing an array predesigned for a particular analyte. To illustrate both aspects, an eight-sensor array utilizing colorimetric sensor materials showing selectivity for fluoride and pyrophosphate while displaying significant cross-reactivity for other anions such as carboxylates, phosphate, or chloride was used to differentiate between 10 anions. The quantitative analyses were also performed to show that the eightsensor array was found to operate across 4 orders of magnitude concentrations (0.20-360 ppm; 10 µM to 20 mM). The applicability of this approach was demonstrated by analyzing several toothpaste brands. The toothpastes are complex analytes comprising both known and unknown anions in various concentrations. The fluoride-selective yet cross-reactive array is shown to utilize the fluoride content as the main differentiating factor while using the remaining anionic components for further differentiation between toothpaste brands.

Supramolekulare Chemie von Anionen: von der Erkennung zur chemischen Anwendung

“…[185] Dies wurde von Anzenbacher et al veranschaulicht, die acht kolorimetrische, in ein Polyurethan-Hydrogel eingebettete Wasserstoffbrückendonor-Sensoren einsetzten (sechs Calixpyrrole, ein N-invertiertes Calixpyrrol und ein Anthrachinon; Abbildung 73), was die Unterscheidung von zehn anorganischen Anionen ermçglichte. [186] Die acht Sensoren wurden auf Grundlage ihrer in organischen Lçsungsmitteln bestimmten Anionenassoziationskonstanten ausgewählt (das Hydrogel desolvatisiert die in der wässrigen Probe vorhandenen Anionen, sodass die neutralen Rezeptoren funktionieren). Die kolorimetrische Reaktion des Arrays auf Anionen wurde mit einem elektronischen Scanner aufgenommen, was die notwendigen computergestützten Berechnungen vereinfachte.…”

Exploration of plasticizer and plastic explosive detection and differentiation with serum albumin cross-reactive arrays

“…[24][25][26][27][28][29][30] The inspiration for differential sensing arises from the mammalian olfactory system, in which there are a finite number of receptors that differentially bind molecules in the vapour phase. 31 The differential response results in a pattern stored in the brain which is recalled as a specific odour.…”

Colorimetric sensing of anions in water using ratiometric indicator-displacement assay

“…This is largely because that the anions are usually larger than isoelectric cations resulting in lower charge-to-radius ratio, a feature which makes the electrostatic binding of anions to the receptors less effective [22,23]. More importantly, the anions have a relatively high free energy of salvation, which indicates that the receptors have to compete with the medium efficiently.…”

“…Sensor array technologies [34,35] have been broadly applied for the determination of toxic industrial gases [36][37][38][39], heavy metal cations [40][41][42], nucleic acid and biomolecules [43,44], diols [45], and even for diagnostics [46]. Array-based cross-reactive fluorescence sensor for multianion detection in water has also been developed recently [22,23]. These sensor arrays show tremendous potential for the identification of multiple anions, however, aqueous solution is always problematic for the hydrogen bonding-based recognition, and limited the sensitivity largely.…”