Red-emitting fluorescent probe for hydrogen sulfide detection and its applications in food freshness determination and in vivo bioimaging.

We report the development of a red-emitting fluorescence probe (XDS) for hydrogen sulfide (HS) detection in biosystems, real-world food samples, and application of this probe for monitoring of HS production during food spoilage. The XDS probe is developed by coupling of coumarin derivative to rhodanic-CN through a HS responsive CC bond. Remarkable fluorescence quenching of XDS is observed as a result of the response to HS. Semi-quantitative detection of HS in three real-world water and two beer samples and monitoring of HS production during food spoilage in real-time by "naked-eye" and smartphone colorimetric analysis are then achieved using XDS as the probe. Moreover, XDS is low toxicity, allowing it being used for visualizing endogenous and exogenous HS in vivo in a mouse model. It is expected that the successful development of XDS could provide an effective tool for investigating the roles of HS in biomedical system and for future food safety evaluation.