A turn-on fluorescent probe with a dansyl fluorophore for hydrogen sulfide sensing.

Hydrogen sulfide (HS) is a biologically relevant molecule that has been newly identified as a gasotransmitter and is also a toxic gaseous pollutant. In this study, we report on a metal complex fluorescent probe to achieve the sensitive detection of HS in a fluorescent "turn-on" mode. The probe bears a dansyl fluorophore with multidentate ligands for coordination with copper ions. The fluorescent "turn-on" mode is facilitated by the strong bonding between HS and the Cu(ii) ions to form insoluble copper sulfide, which leads to the release of a strongly fluorescent product. The HS limit of detection (LOD) for the proposed probe is estimated to be 11 nM in the aqueous solution, and the utilization of the probe is demonstrated for detecting HS in actual lake and mineral water samples with good reproducibility. Furthermore, we designed detector vials and presented their successful application for the visual detection of gaseous HS.