Recyclable fluorescent chemodosimeters based on 8-hydroxyquinoline derivatives for highly sensitive and selective detection of mercury(II) in aqueous media and test strips.

Four novel highly selective 8-hydroxyquinoline-based fluorescent chemodosimeters (1-4) were synthesized for the rapid analysis of Hg in aqueous solution and on paper strips, which probably attributed to the excited state intramolecular proton transfer (ESIPT) process. Chemodosimeter 1 was evaluated as a Hg-ratiometric fluorescent sensor while others (2, 3 and 4) displayed fluorescence turn-on response for Hg among the various survey metal ions. We demonstrated that chemodosimeters (1-4) could recognized Hg ions based on a 1:1 stoichiometric binding event with fast detection time. More importantly, the detection limits for Hg could reach at 10 M level except chemodosimeter 1 (4.05 × 10 M). In addition, it was found that chemodosimeters (1-4) were recycled efficiently because the Hg induced emission spectra were reversed after adding NaBH. Finally, these four sensors were successfully applied for fabrication of simple device test strips for rapid and on-site detection of Hg ions.