A xanthene-based probe with dual reaction sites enables fluorescence turn-on detection of thiophenol in an aqueous medium

Abstract

A xanthene fluorophore-based probe, Xanth-NO₂, has been reported for the detection of thiophenol. Xanth-NO₂ exhibited quenched fluorescence in an aqueous buffer due to its aggregate state, which allows a fluorescence turn-on response via the PhSH-induced transetherification process. In an aqueous buffer, the half-time for the reaction of Xanth-NO₂ with thiophenol is 15 min. There is a linear overlap between the Xanth-NO₂ fluorescence and thiophenol concentrations (0–10 μM), with a 130 nM detection limit. Xanth-NO₂ reacted differently with hydrogen sulfide and thiophenol, allowing us to distinguish between these two analytes. Additionally, the ability of Xanth-NO₂ to detect thiophenol in the presence of competing molecules or ions was demonstrated. Real-water samples and paper strip-based vapour phase detection of thiophenol were used to show the potential use of the reported probe.