A metal-organic framework nanocomposite made from functionalized magnetite nanoparticles and HKUST-1

The author describes the preparation of a magnetic metal organic framework of type MOF-199 containing magnetite (Fe.sub.3O.sub.4) nanoparticles carrying covalently immobilized 4-(thiazolylazo) resorcinol (Fe.sub.3O.sub.4@TAR). This material is shown to represent a viable sorbent for separation and preconcentration of Cd(II), Pb(II), and Ni(II) ions. Box-Behnken design was applied to optimize the parameters affecting preconcentration. Following elution with 0.6 mol L.sup.-1 EDTA, the ions were quantified by FAAS. The capacity of the sorbent ranged between 185 and 210 mg g.sup.-1. The limits of detection are 0.15, 0.40, and 0.8 ng mL.sup.-1 for Cd(II), Ni(II), and Pb(II) ions, respectively. The relative standard deviations are