1,3,4-Thiadiazol derivative functionalized-FeO@SiO nanocomposites as a fluorescent probe for detection of Hg in water samples.

5-Amino-1,3,4-thiadiazole-2-thiol was used to synthesize a novel fluorescent functionalizing group on a FeO@SiO magnetic nanocomposite surface for detection of heavy metal ions in water samples. The prepared probe was characterized by using X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, and a vibrating sample magnetometer. Among various tested ions, the new nanocomposite responded to Hg ions with an intense fluorescence "turn-off". The limit of detection of the probe shows that it is sensitive to the minimum Hg concentration of 48.7 nM. Theoretical calculations were done for estimating binding energies of the three possible bonding modes and the visualized molecular orbitals were presented.