An Imidazo[1, 2-a]Pyridine Based Fluorescent Probe for the Continuous "on-off-on" Detection of Fe3+ and F

Abstract

An "on-off-on" fluorescent probe LK was synthesized from 2-benzoylpyridine and o-vanillin, which could sequentially detect Fe³⁺ and F^- in DMSO/H₂O solutions (v/v = 1/1, HEPES buffer, 1.0 mM, pH 7.0) with large Stokes shift (178 nm). LK exhibited not only high selectivity and sensitivity towards Fe³⁺ and F^-, but also strong anti-interference ability to other ions. LK was coordinated with Fe³⁺ at a ratio of 2:1, with a binding constant (K_a) of 1.3 × 10⁴ M^{- 1}. The detection limits for Fe³⁺ and F^- were 6.9 × 10^{- 8} M and 3.0 × 10^{- 7} M, respectively. Due to its excellent sensing performance, LK was successfully applied in actual water samples and test papers for the detection of Fe³⁺ and F^-.

Keywords: F- ion; Fe3+ ion; Fluorescent probe; Imidazo[1, 2-a]Pyridine.