Single fluorescent chemosensor for multiple targets: sequential detection of Al3+ and pyrophosphate and selective detection of F− in near-perfect aqueous solution

Abstract

A simple and easily fabricated chemosensor (1), based on 2-furoic hydrazide and diethylaminosalicylaldehyde moieties, was devised and synthesized. Sensor 1 showed selective changes in fluorescence behavior toward three analytes in near-perfect aqueous solution. Al³⁺ and F⁻ recognized by fluorescence enhancement of 1 and their limits of detection (0.19 μM for Al³⁺ and 1.9 μM for F⁻) were markedly low compared to World Health Organization guidelines (7.4 μM for Al³⁺ and 79 μM for F⁻) for drinking water. Furthermore, sensor 1 was used to quantify Al³⁺ and F⁻ in real water samples and image Al³⁺ in living cells. Interestingly, the resulting 1–Al³⁺ complex could be used to discriminate pyrophosphate (PPi) over competing anions, including phosphate-based anions, by decreased fluorescence. Sensing mechanisms of 1 toward Al³⁺, PPi, and F⁻ were proposed based on photophysical studies and theoretical calculations.