Preparation Of Magnetic Hybrid Material For The Application On Sample Pre-treatment Methology

Magnetic hybrid materials are series of compounds combing magnetic responsive particles with various functional substances which possess different physical and chemical properties.As the central part of the core-shell composite,magnetic particles can endow the integral material with high superparamagnetism under an external magnetism field.While removing the magnet,the magnetic hybrid particles will be dispersed in aqueous medium again without aggregation due to the modification of exterior coatings.The fast magnetic responsibility and favorable dispersibility of these magnetic hybrid materials are beneficial for adsorption process in magnetic solid-phase extraction.These features make magnetic hybrid materials attract extensive and consecutive attention in the separation and preconcentration field.For magnetic solid phase extraction,the key point of magnetic hybrid material is the selection and modification of the shell part.One or more kinds of materials with specific recognition ability toward the target analyte can be used simultaneously for preparation of the shell.A literature survey revealed that a variety of materials have been adopted,e.g.organic molecules,supermolecule compounds,natural materials and biological polysaccharide.In the present work,we synthesized several kinds of novel magnetic hybrid materials as adsorbents for metal ions or organics.The detailed contents include the followings:1.A magnetic poly ionic liquid with dual task-specific sites was synthesized.The thermal stability was enhanced as well as the specific affinity toward noble metals which stemmed from thiol groups in the cation and anion of poly ionic liquid was introduced.This novel magnetic hybrid material was used as effective adsorbent to preconcentrate gold（Au）and palladium（Pd）in combination with graphite furnace atomic absorption spectrometry.The hybrid material was characterized.Several experiment conditions for magnetic solid phase extraction were optimized.The linear ranges for Au and Pd were in the range of 0.05-0.35 ng mL^-1 and 0.03-0.65 ng mL^-1,respectively.The limits of detection were calculated as 19.7 for Au and 22.3 ng L^-1 for Pd.Enrichment factors were achieved as 197 and 174 for Au and Pd,respectively.2.A magnetic poly ionic liquid modified with carboxylatocalix[4]arene was prepared by ionic complexing in this work.The pore structure was observed after the substitution of anionic port of poly ionic liquid with carboxylatocalix[4]arene,which could facilitate the adsorption of organic molecules.The obtained magnetic hybrid material was applied as adsorbent for magnetic solid phase extraction process to preconcentrate phthalate esters in tap water,tones,and human serum samples combined with high performance liquid chromatography.The limits of detections of this method ranged from 0.02 to 0.31 ng mL^-1 with EFs in the range of 158.7-191.3.The recoveries in the spiked experiments reached in the range from 84.3% to 110.8%.3.A kind of magnetic zeolite,magnetic ZSM-5,was synthesized by solvent evaporation and hydrothermal technique.The magnetic particles were encapsulated and dispersed in the inner space of zeolite.After the silanization with silylated reagents,abundant amino groups were modified onto the surface of magnetic ZSM-5.Carboxylatocalix[4]arene was introduced subsequently by the formation of amide bond between the amino-functionalized magnetic ZSM-5 and the carboxylate-functionalized calix[4]arene.The obtained material was characterized and utilized as magnetic adsorbent for the preconcentration of four kinds of synthetic phenolic antioxidants in milk powder and drink samples combined with high performance liquid chromatography.The limits of detection were within the range from 19.9 to 225.0 ng mL^-1.Enrichment factors and recoveries were calculated within the range of 41.9-92.5.and 81.5-106.2%,respectively.4.A functional monomer by substitution between methacryloyl chloride and iminodiacetic acid was prepared.The magnetic particles with fullerene to enhance the surface area was functionalized as well as a large delocalized π-conjugated structure with higher hydrophobility was provided.Then the obtained functional compound was used as monomer,methylene blue as the template molecule and 2-vinylbenzene as crosslinker to synthesize a new magnetic surface molecular imprinted polymer.The material was used to adsorb methylene blue from water samples combining with ultraviolet-visible spectrometry as well as selected to study the adsorption behavior of methylene blue.The maximum adsorption amount was calculated as 41.46 mg g^-1.The adsorption isotherm results revealed that this adsorption process followed Freundlich isotherm model and the kinetics of the adsorption could be described well with pseudo-second-order equation.The adsorption behavior was multilayer and driven by chemical adsorption mainly.