Kamyar Pourghazi - Faculty of Chemistry, Kharazmi (Tarbiat Moalem) University, Tehran, Iran
Asadollah Beiraghi - Faculty of Chemistry, Kharazmi (Tarbiat Moalem) University, Tehran, Iran
Mitra Amoli-Diva - Faculty of Chemistry, Kharazmi (Tarbiat Moalem) University, Tehran, Iran

A sensitive, fast and cost-effective magnetic solid phase extraction procedure based on ethylene glycol bismercaptoacetatemodified silica coated Fe3O4 nanoparticles was developed. The prepared adsorbents were characterizedby SEM and FT-IR and were used for preconcentration of Hg, Pb and Cd ions in environmental and Food samples. Acomprehensive study on the main factors affecting the extraction and desorption efficiencies such as, pH value, desorptionconditions, sample volume, and amount of adsorbent was presented. Under the optimum conditions, the method waslinear in the range 0.01- 750 ng mL-1 and detection limit was 0.005, 0.007 and 0.002 ng mL-1 for Hg, Pb and Cdrespectively. The relative standard deviation (RSD%) of 1.9, 2.1 and 2.6% (C=50 ng mL-1, n=7) and high enrichmentfactors of 285, 282 and 279 were also obtained for Hg, Pb and Cd respectively. Finally, the method was successfullyapplied to the determination of target metal ions in canned tuna fish samples with satisfactory recoveries.

Magnetic nanoparticles; Ethylene glycol bis-mercaptoacetate; Solid phase extraction, Preconcentration; Heavy metals