Performance comparison of two cascade reaction models in fluorescence off–on detection of hydrogen sulfide

Abstract

Comparative studies on the performances of two cascade reaction based fluorescent H₂S probes are reported. These probes were also designed to address the solubility issues of existing probes. The Reso-N₃ probe favors the H₂S mediated azide-to-amine reduction followed by a cyclization to release the resorufin fluorophore. Reso-Br undergoes a bromide-to-thiol nucleophilic substitution followed by a similar cyclization releasing the same fluorophore. Reso-N₃ exhibited lower background fluorescence and better H₂S sensing behavior in water compared to Reso-Br. Reso-Br underwent hydrolysis in aqueous buffer conditions (pH = 7.4) while, Reso-N₃ was quite stable. Reso-N₃ displayed high selectivity and sensitivity towards H₂S. Live cell imaging of the species by the probe was also established.