An “OFF–ON” fluorescent chemosensor for highly selective and sensitive detection of Al (III) in aqueous solution

•A sensitive and selective Al3+ fluorescent chemosensor based on Schiff's base complex was developed.•The limit of detection for Al3+ is 0.17 μM in aqueous solution.•The chemosensor operated in aqueous solution.•The chemosensor can be applied in fluorescence microscopic imaging.

A Schiff base-type fluorescent chemosensor, 2,2′-bipyridyl-3,3′-bis-(N,N′-disalicylidene)-formyhydrazone has been synthesized and characterized. Among the various metal ions, only Al3+ induces the fluorescence enhancement of the formylhydrazone and results in “OFF–ON” type sensing with excellent selectivity and high sensitivity in aqueous system. The lowest detection limit for Al3+ is 0.17 μM, which is much lower than the permissible concentration of Al3+ for drinking water in China. Also, the chemosensor can be applied to the monitoring of Al3+ ion in aqueous solution with a pH span 6–8. Furthermore, fluorescence microscopic imaging also indicates that the formylhydrazone chemosensor has the potential for the detection of Al3+ in the biological environment.

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