Abstract:

For expedient detection of H₂S in environmental samples, a renewable H₂S fluorescent probe(1-Cu²⁺) was constructed based on a complex formed by coumarin hydrazide oxime fluorescent ligand and a Cu²⁺. The probe displays very weak emission owing to quenching effect of Cu²⁺. The emission could be enhanced in the presence of S^2-, but no obvious changes in fluorescence intensity were observed upon the addition of other relevant anionic analytes(F^-, Cl^-, Br^-, I^-, CO32-, HPO42-, H₂PO4-, NO2-, NO3-, SO42-, CH₃COO^-, N3-, S₂O32-, CN^-). That is to say the probe system exhibits a remarkably selective fluorescence “ON” behavior exclusively with sulfide. The probe could be regenerated by the addition of Cu²⁺, and therefore the probe could be utilized repeatedly to sense sulfide anions with Cu²⁺ and S^2-. The detection limit of the fluorescent assay for sulfide is as low as ~37.0 nmol/L with a rapid response time(a few seconds), and the linear range is 0.5~4.0 μmol/L.

Key words: coumarin hydrazide oxime, Cu²⁺ complex, hydrogen sulfide, renewable fluorescent probe, turn-on type