A novel europium-sensitive fluorescent nano-chemosensor based on new functionalized magnetic core–shell Fe3O4@SiO2 nanoparticles

A novel Eu3+-sensitive fluorescent chemosensor is introduced. It is based on magnetic core–shell silica nanoparticle which is functionalized by Cinchonidine (CD-Fe3O4@SiO2). The nano-chemosensor was synthesized and characterized by Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA), transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV–visible absorption and fluorescence emission. The fluorescent nano-chemosensor shows a selective interaction with Eu3+ ion. Fluorescence studies revealed that the emission intensity of the functionalized magnetic core–shell silica nanoparticles (CD-Fe3O4@SiO2 NPs) increases significantly by addition of various concentrations of Eu3+ ion. While in case of mono, di, and other trivalent cations, weak changes or either no changes in intensity were observed. The enhancement in fluorescence intensity of nano-chemosensor is because of the strong covalent binding of Eu3+ ion to CD-Fe3O4@SiO2 NPs with a large binding constant value of 1.7×105 mol L−1.