Determination of Lead and Cadmium in Various Food Samples by Solid Phase Extraction Using a Novel Amino-Vinyl Functionalized Iron Oxide Magnetic Nanoparticles

A facile method for synthesis of amino functionalized silica coated Fe3O4 magnetic nanoparticles is introduced. For this purpose, the surface of magnetic nanoparticles (MNPs) was modified with two precursors of silica which produced amine and vinyl functional groups on the surface of magnetic nanoparticles. The modified magnetic nanoparticles were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), vibrating sample magnetometry (VSM) and thermo-gravimetric analysis (TGA). Results showed that, in the presence of vinyl precursor, the stability of silica matrix clearly improved. Moreover, the amino functionalized magnetic nanoparticles were used as a sorbent for solid-phase extraction of trace lead and cadmium in different food samples such as rice, wheat, milk and shrimp. The effects of various parameters such as pH, extraction time and adsorbent content were investigated in order to establish the optimum conditions for the extraction and determination of lead and cadmium. The regeneration studies also showed that modified magnetic nanoparticles can be used several times for the adsorption of lead and cadmium without loss of their magnetization properties.