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