Construction of a Flavonol-Based Fluorescent Probe with a Large Stokes Shift for Highly Selective and Rapid Monitoring of H₂S in Water, Foodstuff, and Living Systems

Hydrogen sulfide (H2S) is closely related to food safety, environmental pollution, and human health. Herein, a fluorescent turn-on responsive probe, 3-(2,4-dinitrophenoxy)-7-(4-(diphenylamino)phenyl)-2-(furan-2-yl)-4H-chromen-4-one (DPF-NP), with a large Stokes shift (210 nm) based on the natural product flavonol was synthesized for detecting H2S. DPF-NP showed high selectivity and sensitivity, a low limit of detection (96 nM), and fast response (3 min) for detecting H2S. After reacting with H2S, DPF-NP exhibited strong orange fluorescence (590 nm), attributed to the excited-state intramolecular proton transfer (ESIPT) effect. In addition, the probe DPF-NP could quantitatively monitor H2S in environmental water and food samples (red wine, beer, eggs, milk, and sour bamboo shoots). Furthermore, DPF-NP has been successful in imaging H2S in vegetable tissues, living cells, and zebrafish. Therefore, this work offers an encouraging method for monitoring H2S in environmental pollution, food quality safety, and living systems.