Ultrafast detection of bisulfite by a unique quinolinium-based fluorescent probe and its applications in smartphone-assisted food detection and bioimaging.

Sulfur dioxide (SO2) is one of the major pollutants in the atmosphere, which is highly susceptible to inhalation by the human body and is converted into its derivatives (HSO3-/SO32-), which is hazardous to both human health and the ecological environment. Therefore the detection of SO2 derivatives (HSO3-/SO32-) is very important. In this work, we have prepared ID-QL, a water-soluble fluorescent probe based on the intramolecular charge transfer (ICT) mechanism, it exhibits colorimetric and fluorescent dual-channel response to HSO3- with ultrafast, highly selective and sensitive detection. In particular, ID-QL can be used for quantitative detection of HSO3- in real food samples. We developed a portable test strip for ID-QL and successfully combined it with smartphone to achieve convenient, low-cost and portable detection of HSO3- in real samples. The probe displays good mitochondrial targeting ability and can be used for visual monitoring and imaging of sulfites in live cells and zebrafish.