Bis-Schiff base functionalized Fe3O4 nanoparticles for the sensitive fluorescence sensation of copper ions in aqueous medium

Abstract

A fluorimetric nanosensor based on the bis-Schiff base fluorophore functionalized Fe3O4 nanoparticles (Fe3O4@SiO2-Saloph) has been constructed for the sensation of aqueous Cu2+ ions. The final nanohybrid was thoroughly characterized by various analytical techniques. The characterization data confirmed the successful introduction of the fluorophore and the highly superparamagnetic nature of the nanoparticles. The fluorescence measurement showed that the fluorescence of the nanosensor was pH-dependent. Notably, the fluorescence was significantly reduced after the addition of Cu2+ ions at pH 6.0, and the linear concentration range for Cu2+detecting was 0.03−1 mg/L. The detection limit was measured to be 5.4 μg/L, showing the excellent sensitivity for Cu2+detection. Besides, the nanoparticles exhibited higher selectivity to Cu2+ over other studied interfering cations. Furthermore, the nanosensor demonstrated excellent sensing reversibility and practical applicability in actual water samples. Finally, the adsorption isotherm study suggested that a monolayer complexion of Cu2+ formed on the material surface.