“Turn-On” Fluorescent Biosensors for High Selective and Sensitive Detection of Al3+ Ion

• Main Authors: Pengfei Wang, Lijie Liu, Fanda Meng, Maroof Ahmad Khan, Hui Li
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2020-11-01
• Series: Frontiers in Chemistry
• Subjects: pyrrole hydrazone Schiff base; fluorescent biosensors; detection of Al3+; theoretical calculation; test paper
• Online Access: https://www.frontiersin.org/articles/10.3389/fchem.2020.607614/full

A series of new compounds (1-4) based on pyrrole hydrazone Schiff bases were designed and synthesized. The interactions of these new compounds with metal ions and their fluorescent recognition were investigated. All compounds showed “turn-on” fluorescence in the presence of Al3+ in aqueous solution. Their sensing behaviors with Al3+ were studied using photophysical experiments, ESI-MS spectrometry analysis, 1H NMR titration, and DFT calculation. The detection limits of 1-4 for the analysis of Al3+ were found to reach a 10−8 M level in aqueous solution, which are far lower than the WHO guidelines for drinking water (7.41 mM for Al3+). A high selectivity test paper has been fabricated for Al3+ detection based on sensor 3. Theoretical calculations (DFT) have been carried out to elucidate the configuration of 1-4 and their Al complexes and rationalize experimental absorption data.