Dispersive micro-solid-phase extraction of benzodiazepines from biological fluids based on polyaniline/magnetic nanoparticles composite

Synthesis and application of a novel magnetic metal-organic framework nanocomposite for determination of Cd, Pb, and Zn in baby food samples

This work describes the synthesis and application of a novel magnetic metal-organic framework (MOF) [(Fe3O4-2,5-dimercapto-1,3,4-thiadiazole)/Cu3(benzene-1,3,5-tricarboxylate)2] to preconcentrate trace amounts of Cd(II), Pb(II), and Zn(II) ions. A Box–Behnken design was used to find the parameters affecting the preconcentration procedure through response surface methodology. Three variables including sorption time, amount of the magnetic sorbent, and sample pH were selected as affecting factors in the sorption step, and four parameters including type, volume, concentration of the eluent, and elution time were selected in the elution step for the optimization study. These values were 33 mg, 11 min, 5.7 EDTA, 4.3 mL, 0.64 mol L–l EDTA solution, 16 min, for amount of the magnetic sorbent, sorption time, sample pH, type, volume, and concentration of the eluent, and elution time, respectively. Following the sorption and elution steps, the ions were quantified by FAAS. The limits of detection were 0.10, 0.15, and 0.75 ng mL−1 for Cd(II), Zn(II), and Pb(II) ions, respectively. The relative standard deviations (RSD) of the method were less than 8.3% for five separate batch experiments in the determination of 25 μg L−1 of Cd(II), Zn(II), and Pb(II) ions. The sorption capacity of the magnetic MOF nanocomposite was 155 mg g−1 for Cd(II), 173 mg g−1 for Pb(II), and 190 mg g−1 for Zn(II). Finally, the magnetic MOF nanocomposite was successfully applied to rapidly extract trace amounts of heavy metal ions in baby food samples.

Solid phase extraction of heavy metal ions from agricultural samples with the aid of a novel functionalized magnetic metal–organic framework

This work describes synthesis of a novel magnetic metal–organic framework to preconcentrate the trace amounts of heavy metals. (a) Functionalized Fe₃O₄ by ethylenediamine. (b) Synthesis of the magnetic MOF nanocomposite.

Magnetic nanoparticle based dispersive micro-solid-phase extraction for the determination of malachite green in water samples: optimized experimental design

This paper presents an extraction method based on dispersive-nanoparticle-solid phase microextraction for the preliminary preconcentration and subsequent spectrophotometric determination of trace amounts of malachite green.