A high efficient and lysosome targeted "off-on" probe for sulfite based on nucleophilic addition and ESIPT.

Recently, sulfur dioxide (SO2) fluorescent detection and bioimaging become popular because the fluorescent probes field development and the importance of sulfur dioxide in biological systems. The development of high selectivity and high effient detection sulfur dioxide in biosystem is still a challenge due to interference of related substances. In this work, hydrazine connected by aldehyde was used to high selectively recognize sulfur dioxide based on nucleophilic addition of bisulfite to aldehyde subsequently forming five-ring by hydrogen bond between bisulfite and hydrazine. Thus, the excellent probe with a quick response (30 s) was applied to lysosome targeted fluorescent imaging and detecting sulfur dioxide in mice.