Pyranine functionalized Fe₃O₄ nanoparticles for the sensitive fluorescence detection of Cu²⁺ ions

In this study, a sensitive fluorescence sensor was synthesized for the detection of Cu²⁺ ions based on the quenching of fluorophore. The sensor is composed of pyranine functionalized amino silane shell modified magnetite (Fe₃O₄) core nanostructures. The synthesized nanomaterials were characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Powder Diffraction (XRD), Vibrating Sample Magnetometer (VSM) and Transmission Electron Microscopy (TEM). The fluorescent magnetic nanoparticles were analyzed by fluorescence spectroscopy. The characterization data showed that the magnetic core was highly superparamagnetic with an average particles diameter up to 10 nm. The fluorescence response of Fe₃O₄@-SiO₂-NH₂-Pyr nanosensor towards Cu²⁺ ions showed an enhanced and selective fluorescence quenching. Pyranine functionalized magnetic nanoparticles were found to be highly selective for Cu²⁺ ions without giving any response to other interfering cations and biomolecules. The nanosensor not only provided a sensitive (LOD = 6 nM), fast and selective detection of Cu²⁺ ions but a new fluorescent and biocompatible material with potential uses in biological and environmental fields.