Novel styrylbenzimidazolium-based fluorescent probe for reactive sulfur species: Selectively distinguishing between bisulfite and thiol amino acids

• New styrylbenzimidazolium derivative with dicyanovinyl moiety exhibit sensitivity and selectivity for HSO 3 ˉ and discriminative fluorescence sensing of Cys/Hcy over GSH. • The detection limits of HSO 3 ˉ was estimated to be 0.25 µM. • The styrylbenzimidazolium derivative was used to detect bisulfite in real samples. • The cytotoxicity of styrylbenzimidazolium derivative was examined against the HeLa cells. In this study, a new fluorescent probe containing dicyanovinyl moiety has been designed and synthesized. Fluorescent probe based on styrylbenzimidazolium derivative was reported for the effective detection of bisulfite and distinguish it from biothiols by exploiting dicyanovinyl group as the recognition site. The photophysical properties of the novel styrylbenzimidazolium derivative were assessed by determination of absorption and fluorescence spectra, fluorescence quantum yield, and fluorescence lifetime. Its spectroscopic behavior towards various analytes has been evaluated in aqueous media at a pH of 7.4. The highest increase in fluorescence intensity of compound 5 in the presence of different analytes was observed for sodium bisulfite and the limit of detection was estimated to be 0.25 μM. The styrylbenzimidazolium dye was applied to detect bisulfite in various wine sample using fluorimetry. Finally, the ability of this novel probe to detect HSO 3 − in red wine samples was evaluated.