A colorimetric and fluorescent probe for sulfite/bisulfite based on conjugated benzothiazole derivative and imaging application in living cells

A new colorimetric and fluorescent probe 2 for SO32-/HSO3- detection was developed based on a conjugated benzothiazole derivative. The probe 2 was red color in aqueous solution and became colorless in the presence of SO32-/HSO3-, accompanied by a fluorescence quenching. It was rationalized by an intramolecular charge transfer (ICT) mechanism, where the addition of SO32-/HSO3- to the vinyl double bond broken the conjugation and blocked the ICT process. This probe showed highly selective detection of SO32-/HSO3- compared with other sulfur-containing species and featured a detection limit of 2.01 mu M. Moreover, the present probe was also successfully used for the fluorescence imaging of intracellular sulfur dioxide derivatives in living HeLa cells.