A novel colorimetric and ratiometric fluorescent probe for visualizing SO2 derivatives in environment and living cells

Monitoring sulfur dioxide (SO 2 ) derivatives in environment is of great significance due to their harmful effects to the environment and human health. In this study, a fluorescent probe ( CZBT ) for SO 2 derivatives was prepared from 9-ethyl-9 H -carbazole-3,6-dicarboxaldehyde and 2-methyl-benzothiazolium, which displayed a noticeable color change from yellow to colorless along with a remarkable fluorescence change from yellow to blue in response to HSO 3 − . The probe could quantitatively determine the concentration of HSO 3 − with excellent selectivity, high sensitivity and low limit of detection. 1 H NMR and HR-MS spectra demonstrated that a selective 1, 4-nucleophilic addition occurred on the bridge double bond in CZBT . The probe was successfully used to determine the SO 2 derivatives in several real water samples with good recovery. Furthermore, the probe was employed for monitoring the level of intracellular HSO 3 − in HeLa (human cervical cancer) cells by fluorescence imaging. These results indicated that CZBT has a good capability for monitoring SO 2 derivatives in environment and living cells.