M.R Fattahi Bafghi - Department of chemistry, Faculty of Science, Yazd University, Yazd, ۸۹۱۹۵-۷۴۱, Iran.
S Dadfarnia - Department of chemistry, Faculty of Science, Yazd University, Yazd, ۸۹۱۹۵-۷۴۱, Iran.
A.M Hajishabani - Department of chemistry, Faculty of Science, Yazd University, Yazd, ۸۹۱۹۵-۷۴۱, Iran.

In this paper, we report a new simple, Simultaneously, low cost, selective and sensitive methods based on nanoMagnetic Fe3O4 for Simultaneous separation and preconcentration Cr (III) and Cd (II) befor determination with Graphite Furnace Atomic Absorption Spectrometry. In this method two nono magnetic particles each covered by ligand Cadion for formation of a specific complex with cadmium ion and ligand Ferron for Formation of a specific complex with chromium ion acting as a selective sorbent is held by magnet in two part of a loop. Then, the sample solution is passed through the loop causing selective extraction and preconcentration of analytes on each sorbent. Finally, the two section of the loop separated and each analyte were eluted by proper sorbent and quantified. The major parameters affecting the extraction efficiency were investigated, including the sample pH, sample flow rate, sorbent amount, sample volume, eluent concentration, and eluent volume. The optimum conditions were pH 6.0, a flow rate of 2 mL min−1, 40 mg of magnetic nanoparticles, a sample volume of 40 mL, an eluent concentration of 3 mol L−1 HCL, and an eluent volume of 500 μL. the preconcentration factor was approximately 80. The method was successfully applied to the determination of the analytes in natural water samples.