Extraction and Preconcentration of Trace Amounts of Mercury Using Functionalized Magnetic-Nanoparticles Prior to Their Determination by UV-Vis Spectrophotometry

In this paper, magnetic nanoparticles functionalized by triazene ligand were prepared for extraction/preconcentration of trace amounts of mercury ions in water samples former on its determination with UV-Vis spectrophotometry. The modified magnetic nanoparticles were characterized by the various techniques such as Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM) and X –Ray Diffractometry (XRD). In the separation process, aqueous solution of Hg2+ ion was mixed with Fe3O4 magnetite nanoparticles modified with (E)-1-(2-Ethoxyphenyl)-3-(4-nitrophenyl)triaze-1-ene (ENT), (MNPs@SiO2-ENT) and then external magnetic field was applied for isolation of magnetite nanoparticles containing mercury ions. Experimental conditions for effective adsorption including pH, ENT amount, Fe3O4 NPs amounts, and eluent type have been studied and established. Under the optimal extraction and preconcentration conditions, calibration curve was linear in the range of 4–80 µgL-1 with r2 = 0.9992 (n=20), the limit of detection (LOD) 1.05µg L-1 and enrichment factor was 38, respectively. This technique was successfully used for the determination of Hg (II) in aqueous samples.