A novel multi-purpose convenient Al3+ ion fluorescent probe based on phenolphthalein

In this paper, phenolphthalein and thiophene hydrazide are used as raw materials to design and synthesize a fluorescent probe (FS) that can selectively detect trace amounts of Al3+ ions in dimethyl sulfoxide and ethanol. After FS is combining with Al3+ ions, the photo induced electron transfer (PET) is inhibiting, so it emits strong blue fluorescence (453 nm) to realize the specific detection of Al3+ ions. Tested by Job's plot and Benesi–Hildebrand method, the binding ratio and binding constant of FS and Al3+ ion are 2:1 and 5.6 × 105 M−1, respectively. As shown by the fluorescence gradient concentration testing, the minimum detection limits of FS in DMSO and ethanol were 2.75 × 10−8 M and 1.8 × 10−8 M, respectively, both of which were lower than the WHO standard for Al3+ ions in drinking water (7.41 µM). FS fluorescent probes can be prepared as detection solvents and test strips for a wide range of applications in the detection of trace Al3+ ions.