Selective chemodosimetric 'Turn-On' fluorescence sensor for HSO3-: Comparing the reactivity of the exocyclic vs. non-exocyclic C=C double bond

The present report deals with specific colorimetric (naked-eye) and fluorometric sensing of HSO3- by a pair of chemodosimetric probes, namely L-1 and L-2. The D-pi-A structure-based probes exhibited an outstanding HSO3 dependent response with excellent selectivity and lower detection limit values. The probes were designed to verify the reactivity of exo-cyclic vs. non-exocyclic C=C bonds towards reaction-based sensing. It was proven that only activated exo-cyclic C=C double bonds were responsible for selective sensing. We also reported the utility of probe-coated paper-strip analysis with L-1 for rapid detection of HSO3- in the experimental medium. Also, the ability to detect HSO3 in real food sample as well as in river water, lake water, and tap water were also checked by L-1.

Automated summary

This report discusses the specific colorimetric and fluorometric sensing of HSO3- by a pair of chemodosimetric probes, showing excellent responses, selectivity, and detection limits. The reliability of selective sensing was ensured through verification of activated exo-cyclic C=C double bonds. The probes have a wide range of applications, including paper-strip analysis and detection of HSO3- in real environmental samples.