A magnetic metal-organic framework as a new sorbent for solid-phase extraction of copper(II), and its determination by electrothermal AAS

We report on the synthesis of Fe3O4-functionalized metal-organic framework (m-MOF) composite from Zn(II) and 2-aminoterephthalic acid by a hydrothermal reaction. The magnetic composite is iso-reticular and was characterized by FTIR, X-ray diffraction, SEM, magnetization, and TGA. The m-MOF was then applied as a sorbent for the solid-phase extraction of trace levels of copper ions with subsequent quantification by electrothermal AAS. The amount of sorbent applied, the pH of the sample solution, extraction time, eluent concentration and volume, and desorption time were optimized. Under the optimum conditions, the enrichment factor is 50, and the sorption capacity of the material is 2.4 mg g(-1). The calibration plot is linear over the 0.1 to 10 mu g L-1 Cu(II) concentration range, the relative standard deviation is 0.4 % at a level of 0.1 mu g L-1 (for n = 10), and the detection limit is as low as 73 ng L-1. We consider this magnetic MOF composite to be a promising and highly efficient material for the preconcentration of metal ions.