Ratiometric and colorimetric fluorescent chemosensor for Ag+ based on tricarbocyanine

• A tricarbocyanine compound was synthesized and used as chemosensor to recognize Ag+.
• The chemosensor can be applied to detect Ag+ by color and fluorescent ratio changes.
• The chemosensor shows high selectivity for Ag+ over other metal ions.
• The chemosensor has been used for Ag+ in real samples successfully.

A novel ratiometric and colorimetric fluorescent chemosensor based on tricarbocyanine (1) for Ag+ has been designed and synthesized. In comparison with Ag+ chemosensors reported, our chemosensor can detect Ag+ in aqueous solution by both color changes and fluorescent ratio changes with long emission wavelength. Upon addition of Ag+ to solutions of 1, observable color change from blue to light red and remarkable shift from 758 nm to 565 nm in emission spectra occur. Under optimized experimental conditions, the chemosensor exhibits a stable response to Ag+ over a concentration range from 5.0 × 10−7 to 2.0 × 10−5 M, with a detection limit to 2.0 × 10−7 M. Most importantly, the fluorescence changes of the chemosensor are remarkably specific for Ag+ over other metal ions. In addition, the proposed chemosensor has been successfully applied for the determination of Ag+ in real water samples which demonstrates its value of practical applications in environment.