【作者】 王岩；

【导师】 崔占臣；

【作者基本信息】 吉林大学 ， 高分子化学与物理， 2014， 博士

【摘要】 分子印迹技术（Molecular imprinting technique, MIT）是一种集高分子化学、材料学、生物化学于一体的新兴技术，具备预定性、特异性和实用性的特点。由MIT制备的分子印迹聚合物（MIPs）是一种对模板分子具有特异选择性的材料，这种材料具有化学性质稳定，选择性和亲和性高，容易制备等优点，所以在很多领域被广泛应用，如模拟酶催化、药物手性分离、固相萃取、生物传感器等。实现模板分子的印迹一般都需要经过三个过程：先是模板与单体形成可逆的预聚体；再加入交联剂通过引发剂引发聚合形成高聚物；最后洗脱去除模板，使得模板在高聚物上留下一个印迹。分子印迹微球（Molecular imprinting microspheres）比表面积大，能使模板分子更易进入到识别位点，从而加速结合动力学，因此十分受到研究者的亲睐。近年来分子印迹微球已被广泛实际应用，如用作酶替代品，药物传递系统，抗体替代品，以及毛细管电泳和传感器。固相萃取（Solid-phase extraction，SPE）是一种高效的样品前处理技术，通过活化、上样、淋洗和洗脱四个过程，就能对样品进行富集和净化，减少样品前处理时间。与传统的液液分配相比，SPE具备操作简单、省时省力、对环境污染小等优点。但是传统的固相萃取材料（C8、C18、佛罗里硅土）选择性比较低，而分子印迹聚合物在三维空间里与目标分子的大小、形状都是特异性匹配，所以将分子印迹技术和固相萃取技术结合既可以对目标分子高度亲和，还可以对目标物高度富集，实现对目标分析物的特异性吸附，回收率满足固相萃取要求。氯代乙酰胺类除草剂是一类高选择性的触杀型除草剂，被广泛应用于水田和旱田。由于氯代乙酰胺类除草剂的大量使用，对土壤和水等环境造成一定的污染，危害人类健康。本论文的主旨是利用假模板法制备一种对氯代乙酰胺类除草剂有类特异性吸附的分子印迹固相萃取（MISPE）材料，并将该材料应用于氯代乙酰胺类除草剂的残留分析。本文主要阐述了氯代乙酰胺类除草剂分子印迹聚合物的制备，对聚合物的性能和识别机理进行表征和研究，将制备的聚合物应用于固相萃取实验，通过优化固相萃取条件，将MISPE应用于土壤样品的分析。本论文的第一章为文献综述，主要介绍了分子印迹技术的起源、发展和应用，简单介绍了分子印迹的最新进展；同时介绍了固相萃取技术。在本论文的第二章，利用沉淀聚合和本体聚合，分别以甲基丙烯酸（MAA）和4-乙烯基吡啶（4-VP）为功能单体，乙二醇二甲基丙烯酸酯（EDMA）为交联剂，以乙腈、氯仿、甲醇为致孔剂在引发剂偶氮二异丁腈（AIBN）引发下合成了以丁草胺为模板的一系列印迹聚合物。并对聚合条件进行了优化，选择最优合成条件。实验结果表明：当以MAA为单体，乙腈为致孔剂，模板分子:功能单体:交联剂的摩尔比为1:4:20时，沉淀聚合制备的分子印迹微球对丁草胺具有较好的结合特性，结合量为8.98mg·g-1。在本论文的第三章，分别用红外光谱仪、粒径分布仪、扫描电镜来表征分子印迹聚合物的结构，粒径分布及形态。通过动力学、平衡吸附和选择性实验来研究MIPs的性能。实验结果表明：各组分都已成功聚合，沉淀聚合制备的微球粒径分布均匀，D50(MIPs)=0.80μm，聚合物呈微球状。动力学实验表明聚合物在60min内达到吸附平衡；平衡吸附法表明MIPs的吸附性能比非印迹聚合物（NIPs）的吸附性能高，在印迹聚合物内存在着特异性结合位点；通过Scatchard分析，证明MIPs内存在着一类特异性结合位点，结合位点的离解常数Kd=12.95mol/L，最大表观结合量Qmax=25.74mg/g，NIPs内存在着一类非特异性结合位点，结合位点的离解常数Kd=42.02mol/L，最大表观结合量Qmax=23.48mg/g；选择性实验表明，分子结构上的差异是造成吸附性差异的主要原因，MIPs对氯代乙酰胺类除草剂（丁草胺、丙草胺、乙草胺、甲草胺、异丙甲草胺）的结合主要发生在聚合物的识别位点上。MIPs对乙草胺有较好的选择性，选择因子α=0.79。在本论文的第四章，用聚合物作为固相萃取的填料，考察了它对丁草胺及其结构类似的氯代乙酰胺类除草剂的固相萃取，讨论了淋洗溶剂种类、洗脱溶剂的体积对萃取效果的影响，并对固相萃取条件进行优化。实验结果表明：以MIPs作为填料的固相萃取柱对氯代乙酰胺类除草剂表现了良好的吸附性，用1mL浓度为1μg/mL的丁草胺、丙草胺、乙草胺、甲草胺、异丙甲草胺的石油醚标准溶液上样，2mL正己烷为淋洗剂，15mL甲醇为洗脱剂时，回收率在90%左右，固相萃取效果最好。在本论文第五章，将农药残留分析与分子印迹固相萃取相结合,将添加丙草胺、乙草胺、甲草胺、异丙甲草胺的土壤样品经分子印迹固相萃取净化后，丙草胺、乙草胺、甲草胺、异丙甲草胺的平均添加回收率分别为85.6%、88.4%、85.6%、82.2%，均达到农药残留分析要求，净化效果良好。因此，本实验利用假模板法制备的分子印迹微球有望在氯代乙酰胺类除草剂残留分析中得到更广泛的实际应用。更多还原

【Abstract】 Molecular imprinting technique is one of the emerging technologies containing polymerchemistry, materials science, biochemistry with predetermination, recognition, practicability.Molecular imprinting polymers (MIPs) prepared by molecular imprinting technique promiseunmatched selectivity for template molecules. MIPs have been widely used in enzyme mimicscatalysts, chiral separation, solid-phase exatraction and biosensors due to their high chemicalstability, high selectivity and affinity, easy availability. Imprinting process generally go throughthree steps: firstly, template and monomer form a reversible complex; then template-monomercomplex polymerized to form a crosslinked polymer; Subsequent elimination of the imprintedmolecule tailor a cavity in the polymer matrix that are complementary to the template.Molecular imprinting microspheres have higher surface area-to-volume ratios; thus,imprinted cavities are more easily accessible by the templates and the binding kinetics areimproved. They have already been used as enzyme substitutes drug delivery systems andantibody substitutes as well as in capillary electrophoresis and in sensors.Solid-phase extraction (SPE) is a time efficient technique of sample pretreatment whichcan enriched and purified sample via conditioning, loading, washing and eluting. SPE havebeen well accepted preconcentration technique with the advantages of simple, less cost andpollution compared with the traditional liquid-liquid distribution. Most common sorbents usedin SPE, for example C8, C18, Florisil, lack selectivity for the target compound. However, MIPspossess specific binding sites that are complementary to the template in terms of its shape, size,and functionality. Accordingly, the combination of molecular imprinting and solid-phaseextraction (MISPE) would inherit both advantages of well selectivity and high extractionefficiency.Chloroacetamide herbicides are a class of highly selective herbicide widely used in paddyand upland. Due to the extensive use of chloroacetamide herbicides, they cause a certain degreeof pollution on the environment and endanger human health. The objective of this paper is to prepare MISPE material which has class-specialadsorption to chloroacetamide herbicides using dummy template and this material can beapplied to chloroacetamide herbicides residue analysis. The preparation of chloroacetamideherbicides molecularly imprinted polymers are described in this paper. The performance andmechanism of recognition are researched. The prepared MIPs are used in solid-phase extractionexperiments and the conditions of solid-phase extraction are optimized. At last, the sample ofsoil is analyzedIn chapter1, there is a literature review, we mainly introduce origin, development andapplication of molecular imprinting technology, the latest advances in molecular imprinting isalso introduced. Meanwhile, we describe the solid phase extraction techniques.In chapter2, a series of butachlor molecularly imprinted polymers are prepared viaprecipitation polymerization and bulk polymerization using MAA and4-VP as functionalmonomers, EDMA as crosslinker, AIBN as initiator agent，acetonitrile, chloroform andmethanol as porogen. The conditions of polymerization are discussed and the optimumsynthesis conditions are selected. The results indicate that the MIPs prepared by precipitationpolymerization employing MAA as functional monomer, acetonitrile as porogen with the molarratio of1:4:20(template: functional monomer: crosslinker) show good binding property, theamount of binding is8.98mg·g-1.In chapter3, the structure, particle size distribution and morphology are characterized byinfrared spectrometry, zetasizer and scanning electron microscopy. The kinetics, equilibriumadsorption and selectivity of MIPs are also studied. The results indicate that all componentshave been successfully polymerized, the particles of precipitation polymerization distributeuniformly, D50(MIPs)=0.80μm, the shape of MIPs is microsphere. Kinetic experiments showthat the adsorption of polymer attain equilibrium within60min; Equilibrium adsorption showthat MIPs have better adsorption capacity than NIPs, because there are many specific bindingsites in MIPs; Scatchard analysis prove one specific binding site exist in MIPs, the Kd andQmax are found to be12.95mol/L and25.74mg/g, respectively. One non-specific binding siteexists in NIPs, the Kd and Qmax are found to be42.02mol/L and23.48mg/g, respectively.Selective experiments show that the difference of adsorption are caused by molecular structure,the adsorption of MIPs to chloroacetamide herbicides (butachlor, pretilachlor, acetochlor,alachlor, metolachlor) are occurred in specific binding site of MIPs. MIPs have betterselectivity for acetochlor, α is calculated to be0.79.In chapter4, an annalyticl procedure based MISPE to butachlor and its structuralanalogues is developed. The types of washing solvent and volume of eluting solvent are discussed, and the conditions of solid-phase extraction are optimized. The experimental resultsindicate that MISPE for chloroacetamide herbicides show good adsorption, using1mL of1μg/mL butachlor, pretilachlor, acetochlor, alachlor，metolachlor petroleum ether solution asloading solvent,2mL hexane as washing solvent,15mLmethanol as eluent, the recoveries ofsolid-phase exactration are about90%.In chapter5, the sample of soil spiked with pretilachlor, acetochlor, alachlor，metolachloris analysed. The average spiked recoveries are85.6%88.4%,85.6%and82.2%, respectively.The results meet the requirement of pesticide residue analysis.Therefore, the present study of the molecular imprinted polymers using dummy template isexpected to be used in chloroacetamide herbicides residues of the practical application.更多还原