A naked-eye fluorescent chemodosimeter based on rhodamine-pyridazine conjugate L was synthesized and characterized. L exhibited high selectivity and excellent sensitivity in both absorbance and fluorescence detection of Cu(2+) in aqueous solution with a broad pH span (1-10). The detection limit of the probe was shown to be up to 0.336 ppm. A simple paper test-strip system for the rapid monitoring of Cu(2+) was developed, indicating its convenient use in environmental samples. Furthermore, fluorescence imaging experiments of Cu(2+) in living MGC803 cells demonstrated its value of practical applications in biological systems.

A novel colorimetric and off-on fluorescent chemosensor which contained a strong electron-withdrawing group was synthesized. As expected, the chemosensor exhibited high selectivity and excellent sensitivity in both absorbance and fluorescence detection of Fe 3? (H (CH 3 OH, H 2 O) = 3/7, 1 mM Tris-HCl buffer, pH = 7.40). Upon addition of Fe 3? , the solution of the chemosensor resulted in a color change from colorless to obvious pink. These significant changes in color could be used for naked-eye detection. Furthermore, fluorescence imaging experiments of Fe 3? ions in living MGC-803 cells demonstrated its value of practical applications in biological systems. Graphical abstract