A red fluorescence probe for reversible detection of HSO3−/H2O2 and its application in food samples and bioimaging

Reducing agent SO2 and oxidant H2O2 are two essential substances in cells, and the balance between them is closely related to the survival of cells. SO2 derivative HSO3- is often used as food additive. Therefore, simultaneous detection of SO2 and H2O2 is of great significance in biology and food safety. In this work, we successfully developed a mitochondria-targeted red fluorescent probe (HBTI), which has excellent selectivity, high sensitivity and large Stokes shift (202 nm). HBTI and HSO3-/SO32- undergo Michael addition on the unsaturated C=C bond, and the addition product (HBTI-HSO3-) can react with H2O2 to restore the conjugated structure. Fluorescence changes from red to non-emissive and then restores to red, and can be detected quickly and visually. In addition, HBTI has been successfully targeted mitochondria, and achieved dynamic reversible response to SO2/H2O2 in living cells, and has been successfully applied to detect SO2 in food samples.