A reversible turn-on colorimetric and fluorescent sensor for Al3+ in fully aqueous media and its living cell imaging

A reversible fluorescent-colorimetric Schiff-base receptor (L) derived from julolidine and aminourea was developed for the selective sensing of Al 3+ ions in buffered aqueous medium. Sensor L demonstrated the presence of Al 3+ ions by both fluorescence enhancement and an instantaneous color change of solution from colorless to yellow. L forms complex with Al 3+ in 1:1 ratio as supported by Job’s plot analysis and mass spectroscopic measurement. The sensitivity of the fluorescent based assay (4.67   nM) for Al 3+ is far below the WHO acceptable limit (7.41   μM) in drinking water. Furthermore, L was employed for imaging the Al 3+ ion in living biological cells.