A ratiometric fluorescent sensor with a large Stokes shift for imaging zinc ions in living cells.

The ratiometric fluorescent sensor based on furoquinoline has been designed and synthesized, and not only exhibits a large Stokes shift of 199 nm in a mixture of C(2)H(5)OH-H(2)O (v/v = 8 ratio 2, 10 mM Tris-HCl, pH = 7.3), but can selectively detect zinc ions in the presence of competing metal ions with a red-shift of 75 nm; moreover, cell stain experiments show that can readily reveal a change in intracellular Zn(2+).