A novel “AIE+ESIPT” mechanism-based fluorescent probe for visual alternating recognition of HSO3−/H2O2 and its HSO3− detection in food samples

Maintaining redox homeostasis in organisms plays a crucial role in human life and health, and changes in the levels of SO2 and H2O2, as typical representative substances of reductants and oxidants, directly affects intracellular redox homeostasis. Hence, it is necessary to manufacture fluorescent probes that can detect HSO3− and H2O2. In this work, a benzopyrylium salt containing benzothiazole derived fluorescent probe HBTO-H with dual properties of aggregation-induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT) has been developed. The probe displays rapid and reversible test of HSO3− and H2O2 in DMF/Tris (v:v = 2:8, pH = 7.3, Tris 10 mM) mixed solvent with high selectivity, good anti-interference ability and a wide applicable pH range (6–11). The detection limits of HBTO-H for HSO3− and H2O2 are 0.187 μM and 0.152 μM, respectively. The response mechanisms of HBTO-H toward HSO3− and H2O2 have been demonstrated to be Michael addition reaction and its retro-reaction based on 1H NMR and HRMS analyses. In addition, HBTO-H has been successfully applied to check HSO3− in sugar and wine specimens. Moreover, HBTO-H was proved to be mitochondria-targetable and can alternately detect exogenous HSO3− and H2O2 in MCF-7 cells, which is desired to be applied to trace HSO3− in organisms in the future.