Construction of a flavonol-based colorimetric and fluorescent probe with large Stokes shift for detecting hypochlorous acid in foodstuffs and imaging in living cells, zebrafish and plants tissues.

The excessive addition of hypochlorous acid (HClO) during food preservation can reduce the nutritional value of foodstuffs, and its abnormal levels in organisms will affect normal physiological and pathological activities. Herein, an efficient fluorescent probe HTTPC for monitoring HClO in foodstuffs and biosystems has been developed from natural flavonol. HTTPC itself emitted intense orange fluorescence emission in nearly 100 % aqueous solution, and it underwent a remarkable fluorescence quenching effect after being treated with HClO. HTTPC could selectively recognize HClO over other different biologically relevant species. Moreover, HTTPC featured many distinguished sensing properties, including large Stokes shift (184 nm), low detection limit (4.7 nM), strong anti-interference capability and rapid response to HClO (10 s). Furthermore, HTTPC can serve as a potential approach for qualitative determination of HClO residues within foodstuffs with good recoveries. HTTPC exhibited outstanding biocompatibility and low cytotoxicity, and it could successfully achieve the real-time fluorescence imaging of HClO fluctuations within live HeLa cells, zebrafish and onion tissues.