▎ 摘　　要

The sensitive and selective analytical methods for real-time monitoring of sulfur dioxide and its derivatives are significant for human health, pollution-control and food safety. Herein, we report a new nanocomposite (Hex-FGO-DPS) consisting of cyanine dye and fluorescent graphene oxide with unique reactive properties for ratiometric fluorescent detection of bisulfite. The ratiometric fluorescence of Hex-FGO-DPS in aqueous solution can be sensitively, selectively and efficiently tuned by bisulfite through a specific nucleophilic addition reaction. In the presence of bisulfite, the ratiometric fluorescence intensity of Hex-FGO-DPS (F-470nm/F-580mn) changes up to 25 folds, accompanied by a distinct color change from yellow to blue which can be visually identified. The detection limit was measured to be 0.44 mu M. The probe can be further applied for sensing intracellular bisulfite through the ratiometric fluorescence imaging analysis in living cells. In addition, the probe Hex-FGO-DPS also can be used for selective determination of gaseous sulfur dioxide in atmosphere and aqueous solution. The simple, sensitive and effective strategy reported here could facilitate the development of portable and reliable sensor for visual identification applications. (C) 2017 Elsevier B.V. All rights reserved.