s Mohajer - Department of chemistry, Faculty of scie nces, Ferdows i university of Mashhad, Mashhad, Iran
m chamsaz - Department of chemistry, Faculty of scie nces, Ferdows i university of Mashhad, Mashhad, Iran
m.h entezari - Department of chemistry, Faculty of scie nces, Ferdows i university of Mashhad, Mashhad, Iran
t rohani bastami - Department of chemistry, Faculty of scie nces, Ferdows i university of Mashhad, Mashhad, Iran
n taheri - Department of chemistry, Faculty of scie nces, Ferdows i university of Mashhad, Mashhad, Iran

Chrom ium is mainly present as Cr(III) a nd Cr(VI) oxidation states. The p roperties of these species are very different fro m a chemical and toxicological points of view [ ۱]. Determin ation of chromium spec ies is prefe rred by AA S due to its simplicity and its lowe r cost compare to other instrumental techniques, but due to its low detection limit, a preconcentration ste p for trace levels of element would be need ed. Among various me thods, SPE has found very important place in speciation studies of m etal ions d ue to its simplicity, selectivity, flexi bility and rapid phase se paration. In SPE proced ures, the choice of the s orbent is a key point because it can control the analytical p arameters such as selectivity, affinity and capacity [۲]. Ma gnetic nanocomposites, have gaine d more atte ntion in a nalytical at omic spectrometry for trace analysis and speciation research owing to its suitability for bulk solution, easy control and fast magne tic separati on under an extra magne tic field [۳].

Chromium speci ation, Magnetic nanoco mposite, Preconcentration, Flame at omic absorp tion spectro metry, Ultr asonic irradiation