A "turn-on" fluorescent and colorimetric chemodosimeter for selective detection of Au3+ ions in solution and in live cells via Au3+-induced hydrolysis of a rhodamine-derived Schiff base

A chromogenic and "off-on" fluorogenic chemodosimeter (L) based on a naphthalene-rhodamine B derivative was designed, synthesized and characterized for the selective and sensitive detection of Au3+ ions in mixed acetonitrile aqueous medium in the presence of other competitive analytes. Probe L displayed a 696-fold "turn-on" fluorescence signal enhancement toward Au3+ ions with the detection limit of Au3+ of about 1.51 mu M. In the presence of Au3+ ions, probe L also exhibited a visible color change from colorless to pink that could be easily identified by the naked eye. This colorimetric and fluorometric changes were mainly due to the Au3+ ion-triggered imine bond (C=N) hydrolysis sensing mechanism. Moreover, theoretical calculations were performed to explain the experimental results. In addition to these features, the "off-on" probe was successfully used to monitor intracellular Au3+ ions in living MC3T3 cells through fluorescence imaging.