Development Of Separation And Enrichment Approaches Based On Novel Magnetic Extractants

Magnetic nanoparticle is a kind of super-fine powder that composes of metal,metal oxide or their composites with magnetic responsive property. It not only hasthe general characteristic of small scale effect and quanta effect, but also has theproperties of unique magnetic response. Recently, magnetic materials have attractedparticular attention due to their unique physicochemical property and theconvenience of magnetic separation and recovery. However, pure Fe3O4particles arevery active, and prone to agglomeration and oxidation. When the magnetic particlesare modified by physical and chemical methods, mainly in order to compensate forthe defects of single particle, it can not only improve the stability and dispersibilityof the particles in solvent, but also enhance the oxidation resistance andbiocompatibility of the particles. Thus the surface modification of magnetic particlesbecomes a hot topic.Magnetic solid phase extraction is a widely used method for preconcentrationand separation of trace target analyte because of its special advantages such assimple, less organic solvent consumption, good selectivity, easy magnetic separation,and easy to combine with flow injection analysis. When organic extractants aremodified on the magnetic microsphere, the obtained extractant-coated magneticadsorbent has the prominent advantage that it can solve the problem of solid-liquidseparation existing in the conventional adsorbent. In this work, two kinds of novelmagnetic extractants were synthesized as the solid phase extraction materials for theseparation and preconcentration, and a series of experiments is launched around theiradsorptive property.(1) A novel magnetic adsorbent (FSC-C272) is synthesized as a noveladsorption material. The material is enclosed in a microcolumn to build a flow injection-magnetic solid phase extraction system (FI-MSPE) to preconcentratephenol prior to the determination by UV-Visible spectrophotometry (UV). Variousexperimental parameters have been optimized in detail including sample flow rate,sample volume, sample pH, eluent, and eluent flow rate. Under the optimumconditions, the proposed method has been successfully applied to the determinationof phenol in phenol ear drops, compound borax solution, and phenol ointmentsamples with the recovery range of95.4104.4%.(2) The crown ether-functionalized magnetic nanoparticle (CEMNs) issynthesized as a novel adsorption material. The material is packed in themicrocolumn to build a FI-MSPE-GFAAS system for the preconcentration anddetermination of Au, Pd, and Pt combined with the graphite furnace atomicabsorption spectrometry. The properties of the magnetic adsorbents wereinvestigated by scanning electron microscope (SEM), X-ray diffraction (XRD), andvibrating sample magnetometer (VSM). Various experimental parameters affectingthe preconcentration of Au, Pd, and Pt were investigated and optimized. Under theoptimal experimental conditions, the detection limits of the developed techniquewere0.16ng mL1for Au,0.28ng mL1for Pd, and1.01ng mL1for Pt,respectively. The developed method was validated by the analysis of Au, Pd, and Ptin certified reference materials and mine samples with the recovery range of...