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

Abstract: 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. [Copyright &y& Elsevier]