Reversible colorimetric and NIR fluorescent probe for sensing SO₂/H₂O₂ in living cells and food samples

Preservative sulfur dioxide (SO₂) and bleach hydrogen peroxide (H₂O₂) were widely used in the food industry, at the same time, they were also a redox pair in biological systems. Therefore, the reversible sensing SO₂/H₂O₂ was of great significance in food safety and biology. In this paper, a colorimetric and NIR fluorescent dual channels response probe (DCA-Bba) for SO₂/H₂O₂ based on chromene-barbiturate was developed. DCA-Bba exhibited a rapid and sensitive recognition of SO₂, and the adduct DCA-Bba-HSO₃^- could detect H₂O₂ in PBS (with 10 % DMSO, v/v, pH 7.4) solution. The reversible response of DCA-Bba was implemented by HSO₃^- involved 1,4-addition and H₂O₂ induced elimination reaction. DCA-Bba showed a strong red fluorescence based on the intramolecular charge transfer (ICT) process, after the recognition of SO₂, the fluorescence of the adduct was quenched based on the photoinduced electron transfer (PET) process. And importantly, DCA-Bba had been applied for imaging SO₂/H₂O₂ redox cycles in living cells, as well as could detect the levels of SO₂ in white sugar, biscuit, Chinese liquor and red wine samples.