Fluorion-deprotonated fluorescent sensor for the highly sensitivity detection of trace water in chemical reagents and application in inkless writing

Abstract

A simple diphenylimidazole-based colorimetric and fluorescent sensor (DIB) was successfully synthesized by one step reaction. DIB exhibited excellent selectivity and sensitivity for F- over various other anions with fluorescence enhancement effect. The limit of detection of DIB towards F- was evaluated to be 9.18 × 10-8 M. A plausible sensing mechanism of DIB towards F- had been proposed on the basis of spectral analysis and 1H NMR titration experiments, which the results suggested that the recognition process could be attributed to the deprotonation of imidazole group. Interestingly, the F- induced deprotonation system of DIB·F could be employed as reversible sensor for trace water with high sensitivity and instant response. The color change easily recognized by the naked eye and low limit of detection (0.0022 %) improved the detection performance of DIB·F for water. Importantly, the DIB·F system had been successfully applied for the quantitative analysis of water content in experimental chemical reagents. In addition, sensor DIB and DIB·F-incorporated filter papers could be utilized as inkless writing display device for F- and water detection, respectively, with reusability.