A New Reusable Mercury-Sensitive Turn-On Nano-Chemosensor Based on Functionalized CoFe2O4@SiO2 Magnetic Nanocomposite

A novel "turn-on" nano chemosensor for Hg2+ was developed based on  CoFe2O4@SiO2 nanocomposite. Cobalt nano ferrite particles were decorated with 1,8-naphthalimide dye conjugated with rhodamine dye.  It was characterized using X-ray powder diffraction (XRD), transmission electron microscopy (TEM), FT-IR techniques. A fluorescence enhancement was observed upon binding Hg2+ to two core chromogenic dyes. No significant change in the fluorescence intensity was observed in the presence of other metal ions. The results showed that the functionalized nanocomposite CoFe2O4@SiO2/NR exhibited selective 'turn-on' fluorescent enhancements with Hg2+. Also, the company of magnetic CoFe2O4@SiO2 nanocomposite (with a wide range of applications such as biomedicine, magnetic fluids, magnetic energy storage) and catalysis facilitates the magnetic separation of the Hg (II) from the solution. Nano chemosensor exhibits high selectivity, high sensitivity and fast response to trace mercury ions. Designed nanosensor successfully applied for Hg2+determination at real samples with a linear range of 0.04-0.76 μM of Hg2+ ions. It was successfully applied for the determination of mercury ion in real samples of tap water. It seems that the presence sensor is a suitable candidate for the detection of trace mercury ion in biomedical samples like a human serum.  Also, it is fast and easy control for monitoring of water toxicity of pollutant industries.