Highly sensitive and selective OFF-ON fluorescent sensor based on functionalized Fe3O4@SiO2 nanoparticles for detection of Zn2+ in acetonitrile media

The Fe3O4 nanoparticles [NPs] coated with silica nanoparticles were designed to produce magnetic core–shell Fe3O4@SiO2 NPs, which were modified with rhodamine B derivatives and defined as Fe3O4@SiO2-Rho NPs. The obtained Fe3O4@SiO2-Rho NPs served as a fluorescent OFF-ON nanosensor was utilized to detect Zn2+ selectively in acetonitrile medium. The Fe3O4@SiO2-Rho NPs exhibited selective “turn-on” type fluorescent enhancements and distinct color changes with Zn2+. The Fe3O4@SiO2-Rho NPs also showed a high capacity for removal of Zn2+ at room temperature. The removal efficiency toward Zn2+ was about 87.34%. In addition, the presence of magnetic Fe3O4 particles as core in Fe3O4@SiO2-Rho NPs could facilitate the magnetic separation of the Fe3O4@SiO2-Rho-Zn2+ from the solution.