A Novel Fluorescence Nanoprobing Strategy for Fluoride Anions Detection in Water

A novel fluorescence nanoprobe, quantum dots (QDs)/silver nanoparticles (AgNPs) assembly system, was developed and studied for the simple, fast and reliable determination of fluoride ions (F^–) in water media based on the fluorescence resonance energy transfer (FRET) between thioglycolic acid modified CdTe QDs and citrate capped AgNPs. The surface plasmon resonances (SPR) spectra analysis reveals that the FRET is caused by the hydrogen bonding interactions, which can effectively quench the fluorescence intensity of QDs, and the presence of F^– can break these hydrogen bonding interactions, recovering the fluorescence of the quenched QDs. The developed fluorescence nanoprobe shows the excellent selectivity and sensitivity towards F^– in the presence of other interfering anions. The detection limit for F^– is about 0.1 ppm (3σ), with the linear range of 0.2–3.5 ppm. Furthermore, the real samples were detected and the recoveries were obtained from 95% to 103%.