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

The Fe 3 O 4 nanoparticles [NPs] coated with silica nanoparticles were designed to produce magnetic core–shell Fe 3 O 4 @SiO 2 NPs, which were modified with rhodamine B derivatives and defined as Fe 3 O 4 @SiO 2 -Rho NPs. The obtained Fe 3 O 4 @SiO 2 -Rho NPs served as a fluorescent OFF-ON nanosensor was utilized to detect Zn 2+ selectively in acetonitrile medium. The Fe 3 O 4 @SiO 2 -Rho NPs exhibited selective “turn-on” type fluorescent enhancements and distinct color changes with Zn 2+ . The Fe 3 O 4 @SiO 2 -Rho NPs also showed a high capacity for removal of Zn 2+ at room temperature. The removal efficiency toward Zn 2+ was about 87.34%. In addition, the presence of magnetic Fe 3 O 4 particles as core in Fe 3 O 4 @SiO 2 -Rho NPs could facilitate the magnetic separation of the Fe 3 O 4 @SiO 2 -Rho-Zn 2+ from the solution.