A selective and turn-on acylhydrazone-based fluorescent probe for Al3+ and its practical application

A new probe ABNH with 4-(diethylamino) salicylaldehyde as fluorophore and nicotinate hydrazide as recognition site was prepared and characterized. The recognition performance was investigated by spectra studies. The results shown that probe ABNH had a remarkably high similar to 140 folds fluorescence enhancement upon complexing with Al3+ in ethanol buffer solution. Probe ABNH and Al3+ formed a 1: 1 complex stoichiometry with an association constant of 8.89 x 10(3) M-1. The LOD was determined to be as low as 0.14 mu M with a linear detection range of 0-60 mu M, which was far below the upper limit of Al3+ described by WHO. The detection was unaffected by other competing species except Cu2+ and F-. Probe ABNH has a response time of 30 s and a wide detection pH range of 4-7. The sensing mechanism was studied by NMR titration and theoretical calculations. Probe ABNH was of low cytotoxicity and could be available in further biological application. Probe ABNH was applied in real water samples for the determination of Al3+. Notably, the probe was successfully put into use in test strips and fluorescent films to detect liquid and solid aluminum salts.