Selective detection of BF3 in living cells and environmental water samples using Schiff-base fluorescent probe

Abstract

A new pyrazole naphthalene-based Schiff base (3c) as a colorimetric and turn-on fluorescent sensor for rapid detection of BF3 was developed. Ligand 3c showed a significant fast response and superior selectivity for BF3 with significant color change by naked eye over other competitive species. Sensor probe 3c showed low detection limit (LOD) of 2.46 nM, which was far lower than the previous reports. Based on the Job’s plot, the binding association ratio of 3c with BF3 was found to be 1:1. The sensing mechanism of 3c with BF3 based on the intramolecular charge transfer (ICT) was confirmed by FTIR, 1H NMR titration, ESI mass spectra, and DFT calculation. Moreover, the sensing probe 3c was found to be reversible with the addition of triethylamine (NEt3), which revealed that 3c could behave as a good candidate for BF3 and NEt3 controlled “ON-OFF-ON” mode. Most importantly, probe 3c has been successfully applied to quantitatively detect BF3 species in various water samples, and using low-cost test paper strips as well as living cells.