An imidazo[1,5-α]pyridines-based ratiometric fluorescent probe for sensing sulfur dioxide derivatives in real samples based on a FRET mechanism

Abstract

A novel fluorescence resonance energy transfer (FRET)-based ratiometric emission fluorescent probe AT was designed and developed in which the imidazo[1,5-α]pyridine was served as a FRET donor and tricyanofuran (TCF) as the FRET acceptor to detect SO₃^2-/HSO₃^- based on the Michael addition reaction. Probe AT had a high energy transfer efficiency (95%) and a large pseudo-Stokes shift (259 nm) in EtOH/PBS buffer (5/5, v/v). It also possessed good selectivity and quick response to SO₃^2-/HSO₃^-. There was good linearity between the ratio of fluorescence intensity (F₄₉₉/F₆₄₅) and the concentrations of SO₃^2-/HSO₃^- in the ranges of 1.5-7.5 μM and 9-20 μM, with calculated detection limits (LOD) of 55 nM. In addition, the probe could also detect the concentrations of SO₃^2-/HSO₃^- in real samples such as environmental water and sugar, allowing the probe to be used in a variety of applications.

Keywords: FRET-based fluorescent probe; Imidazo[1,5-α]pyridine; Large pseudo-Stokes shift; Real samples.