A multifunctional fluorescence probe for HSO₃^-/SO₃^2- and viscosity in real samples and living cells

The abnormal levels of sulfite and viscosity are intimately associated with some physiological processes in vivos. As an important reducible species, sulfite is extensively existed in food and living cells. However, lacking an effective molecular tool to track sulfite and viscosity in food and living cells. Herein, a novel fluorescent probe (named JFL) with a deep red emission window (628 nm) and large Stokes shift (178 nm) basing on FRET/TICT platform for sulfite and viscosity was prepared. Probe JFL could effectively monitor the increasing of sulfite level with a ratiometric feature that a continuously increased green emission signal at 536 nm and a gradually decreased red emission signal at 628 nm. JFL tracks sulfite with low detection limit, wide linear range (0-100 μM), high sensitivity and selectivity. Meanwhile, JFL could also detect vicosity relying on the continuous increments of emission signal at 628 nm with the viscosity level increasing. Significantly, probe JFL could effectively detect the varying of sulfite and viscosity in real food samples and living cells.