Synthesis of nanoflower-shaped covalent organic framework fluorescent probe for sensitive detection of aluminum ions

The widespread application of aluminum has led to numerous adverse effects on organisms due to aluminum pollution. In this study, we synthesized a two-dimensional fluorescent covalent organic framework (TAPB-DMTP-COF) material with nanoflower morphology for fluorescence detection of aluminum ions. The coordination binding of Al3+ with the nitrogen atoms on the imine bonds and the oxygen atoms on the methoxy groups restricts intramolecular rotation in TAPB-DMTP-COF, which inhibits the photo-induced electron transfer (PET) in the COF molecule and triggers the fluorescence emission "turn on" phenomena. A fluorescence method for Al3+ detection was established, and it was found that the method exhibits high sensitivity, selectivity, a wide detection range from 4.0 to 100.0 μM, and a low limit of detection (LOD) of 38.5 nM. This work provided new ideas for the convenient and rapid detection of aluminum ions in environmental analysis and expanded the application of fluorescence COFs in analytical sensing.