Reaction-Based Ratiometric and Colorimetric Chemosensor for Bioimaging of Biosulfite in Live Cells, Zebrafish, and Food Samples.

In this work, a reaction-based ratiometric and colorimetric sensor was designed and synthesized for probing bisulfite (HSO) by coupling coumarin () with barbituric () moiety. Further tests have shown that has high selectivity and sensitivity for the recognition of HSO, which can be applied for the detection of HSO in environmental and biological systems very effectively. The fluorescence intensity ratios (/) exhibited an outstanding HSO-dependent response with ultrafast response time (within 20 s) and a lower detection limit (105 nM). Meanwhile, the color of the solution changed from green to colorless during the recognition process, and its fluorescence changed from green to blue. The mechanism of response is confirmed by the density functional theory (DFT) model. In summary, has demonstrated low toxicity and good permeability, which can be applied for imaging HSO in cells and zebrafish safely and effectively. Besides, this novel sensor successfully realized the quantification of the concentration of HSO in paper strips and food samples.