Reaction-based colorimetric and ratiometric fluorescent probe for highly selective detection of silver ions

A novel colorimetric and ratiometric fluorescent probe CHa based on Ag+ induced hydrolysis of hydrazone was designed and synthesized. To the best of our knowledge, this is the first time the ratiometric sensing of Ag+ based on a chemical reaction has been accomplished. When Ag+ was added to a solution of CHa, a visible color change from yellow to colorless and a fluorescence color change from yellow to blue were observed. Probe CHa displayed a 203-fold enhancement of the fluorescence intensity ratio (I-450nm/I-520nm) toward Ag+ with outstanding sensitivity, high selectivity and a low detection limit (LOD 61 nM). Moreover, CHa was successfully applied to the ratiometric imaging of Ag+ in HepG2 and HeLa cells.