A twisted intramolecular charge transfer probe for rapid and specific detection of trace biological SO2 derivatives and bio-imaging applications

We reported a reactive probe for HSO3-, which showed a colorimetric and ratiometric fluorescence response to HSO3- with fast response (t(1/2) = 20 s), good specificity and low detection limit (3.0 nM). The probe was cell membrane permeable and successfully used for visualizing trace SO2 derivatives in living cells.