A colorimetric supramolecular sensor array based on charge-transfer complexes for multiplex aniline and phenolic pollutants detection

Abstract

In order to effectively monitor toxic and harmful substances in sewage discharge, a rapid, highly sensitive detection of complex pollutants with similar structures has become an urgent problem to be solved. In this paper, a supramolecular colorimetric array sensor based on charge-transfer complex was constructed, which can quickly detect aniline and phenol pollutants (such as p-phenylenediamine, m-phenylenediamine, o-phenylenediamine, m-aminophenol, hydroquinone, and resorcinol) with similar structures. When six anilines and phenol isomers with similar structures were added to the supramolecular colorimetric array sensor, different color changes were produced under natural light. Linear discriminant analysis (LDA) showed that the supramolecular colorimetric array sensor could recognize and distinguish these isomers, and a mixture with different concentration ratios could be well categorized. The total Euclidean distance (TED) of an array with pollutant concentrations had a good linear correlation, and the detection limit (LOD) was as low as 10−5-10−6 mol L−1. Six anilines and phenol isomers in real samples were identified by supramolecular colorimetric array sensor. 1H NMR results showed that the formation of charge transfer complexes in Q[8] cavity may be the cause of color change. This work provides a fast and convenient experimental basis for monitoring the complex structure pollutants in sewage discharge.