A simple turn-on fluorescent chemosensor based on Schiff base-terminated water-soluble polymer for selective detection of Al3+ in 100% aqueous solution.

A simple water-soluble polymer PEGBHB based on polyethylene glycol bearing a Schiff base derivative moiety was successfully designed and synthesized. PEGBHB showed high selectivity and sensitivity towards Al3+ as a turn-on fluorescent chemosensor without influence by other competitive metal ions in 100% aqueous solution. The detection limit of PEGBHB for Al3+ was found to be 9.67 × 10-9 M. A 1:1 stoichiometry between PEGBHB and Al3+ has been confirmed by Job plot analysis. PEGBHB could detect Al3+ over a wide pH range from 4 to 10. The chemosensor was reversible by adding EDTA to the solution of PEGBHB-Al3+ complex. An INHIBIT molecular logic gate was constructed with the help of OFF-ON-OFF signal on alternate addition of Al3+ and EDTA to the chemosensor. Furthermore, test papers were fabricated facilely using PEGBHB for convenient and visual detection of practical Al3+.