title: Determination of heavy metal ions in vegetable samples using a magnetic metal-organic framework nanocomposite sorbent.
abstract: This paper describes the synthesis and application of a novel magnetic metal-organic framework (MOF) [(Fe₃O₄-benzoyl isothiocyanate)/Cu₃(benzene-1,3,5-tricarboxylate)₂] to pre-concentrate trace amounts of Cd(II), Pb(II), Zn(II) and Cr(III) ions and their determination by flame atomic absorption spectrometry. A Box-Behnken design was used to find the parameters affecting the pre-concentration procedure through response surface methodology. Three factors including uptake time, amount of the magnetic sorbent and pH of the sample were selected as affecting factors in the sorption step, and four factors including type, volume and concentration of the eluent as well as the elution time were selected in the elution step for the optimisation study. The opted values were 30 mg, 10.1 min, 5.9, EDTA, 4.0 ml, 0.57 mol l(-1) EDTA solution and 13.0 min for the amount of the magnetic sorbent, uptake time, pH of the sample, type, volume, concentration of the eluent, and elution time, respectively. The limits of detection (LODs) were 0.12, 0.7, 0.16, and 0.4 ng ml(-1) for Cd(II), Pb(II), Zn(II) and Cr(III) ions, respectively. The relative standard deviations (RSDs) of the method were less than 7.2% for five separate batch experiments for the determination of 30 μg l(-1) of Cd(II), Pb(II), Zn(II) and Cr(III) ions. The sorption capacity of the [(Fe₃O₄-benzoyl isothiocyanate)/MOF] was 175 mg g(-1) for Cd(II), 168 mg g(-1) for Pb(II), 210 mg g(-1) for Zn(II) and 196 mg g(-1) for Cr(III). It was found that the magnetic MOF nanocomposite demonstrated a higher capacity compared with Fe₃O₄-benzoyl isothiocyanate. Finally, the magnetic MOF nanocomposite was successfully applied to the rapid extraction of trace amounts of the heavy metal ions from vegetable samples.
authors.affiliation: a Department of Chemistry, Marand Branch , Islamic Azad University , Marand , Iran.
authors.forename: Akbar
authors.initials: A
authors.lastname: Hassanpour
authors.forename: Rahim
authors.initials: R
authors.lastname: Hosseinzadeh-Khanmiri
authors.forename: Mirzaagha
authors.initials: M
authors.lastname: Babazadeh
authors.forename: Jafar
authors.initials: J
authors.lastname: Abolhasani
authors.forename: Ebrahim
authors.initials: E
authors.lastname: Ghorbani-Kalhor
mesh_terms: D002104:Cadmium / Q000032:analysis; D002857:Chromium / Q000032:analysis; D005504:Food Analysis; D005506:Food Contamination / Q000032:analysis; D007477:Ions / Q000032:analysis; D007854:Lead / Q000032:analysis; D057230:Limit of Detection; D019216:Metals, Heavy / Q000032:analysis*; D053761:Nanocomposites / Q000737:chemistry*; D015203:Reproducibility of Results; D017550:Spectroscopy, Fourier Transform Infrared; D014675:Vegetables / Q000737:chemistry*; D014961:X-Ray Diffraction; D015032:Zinc / Q000032:analysis
chemical_list: D007477:Ions; D019216:Metals, Heavy; D002104:Cadmium; D002857:Chromium; D007854:Lead; D015032:Zinc
keywords: extraction; food samples; heavy metal ions; magnetic metal–organic frame work nanocomposite