【作者】 申中兰；

【导师】 苏庆德；

【作者基本信息】 中国科学技术大学 ， 分析化学， 2008， 博士

【摘要】 有机磷和有机氯农药是两类广泛使用的杀虫剂,在食品和环境样品中的有机磷和有机氯农药残留的选择性分离分析受到广泛关注。分子印迹技术是近年来国内外得到迅速发展的新型分子识别手段,分子印迹聚合物具有选择性高、稳定性好、使用寿命长以及应用范围广等优点,可高选择性的区分印迹分子及其结构类似物。目前,分子印迹技术已在生命科学、环境检测、天然药物以及食品工业等领域得到广泛应用。基质固相分散过程利用固相分散剂的角质力充分研磨和破坏样品,使样品与分散剂充分接触,达到一步提取净化的效果。加速溶剂萃取法是1995年出现的一种新的固体/半固体样品前处理方法。加速溶剂萃取过程中,用不同极性的有机溶剂在高温(40-200℃)和高压(1000-2500psi)下萃取,可以用少量的溶剂快速提取大范围的目标物质。本论文将分子印迹技术与有机磷农药残留分析相结合,合成了有机磷农药甲胺磷和乙酰甲胺磷分子印迹聚合物;对分子印迹聚合物的结合机理、形貌和性能表征进行了深入的研究;选用合适的固相分散剂,结合基质固相分散和加速溶剂萃取法建立了复杂体系中有机氯农药多残留的分离分析新方法。论文取得的主要研究成果包括:1.采用分子印迹技术制备了对甲胺磷分子有特异选择性的分子印迹聚合物。通过~1H NMR、FT-IR和UV光谱研究了印迹聚合物的结合机理,结果表明甲胺磷与功能单体之间以协同氢键作用形成配位比为1:2的氢键配合物。Freundlichisotherm(FI)拟合结果表明印迹聚合物对甲胺磷具有强吸附能力。饱和吸附甲胺磷前后的印迹聚合物红外光谱研究结果表明聚合物中含有COOH功能基团并通过协同氢键作用特异性识别甲胺磷分子,甲胺磷分子中氨基上的氢原子和磷氧双键中的氧原子是与COOH形成氢键的选择性结合位点。固相萃取实验(MISPE)结果表明分子印迹聚合物对甲胺磷分子有明显的特异性识别。2.相对于甲胺磷(pK_a=10.0),乙酰甲胺磷的碱性(pK_a=8.5)和毒性都较小。以乙酰甲胺磷为模板分子,采用分子印迹技术制备了一种新型分子印迹聚合物。通过~1H NMR、FT-1R和UV光谱研究了印迹聚合物的结合机理,结果表明乙酰甲胺磷与甲基丙烯酸之间以协同氢键作用形成配位比为1:2的氢键配合物,乙酰甲胺磷分子中氨基上的氢原子和磷氧双键中的氧原子是与COOH形成氢键的选择性结合位点。单分析物结合实验结果显示此聚合物对乙酰甲胺磷模板分子和结构较小的甲胺磷都具有较强的吸附能力,固相萃取实验(MISPE)结果与其一致。为土壤和水体中乙酰甲胺磷和极性、毒性较大的甲胺磷的同时分离富集和测定建立了良好的理论和实验基础。3.采用沉淀聚合法合成了直径为3.5μm的甲胺磷微球型分子印迹聚合物,在聚合物形貌、吸附性能、热稳定性及多孔性方面与传统块状聚合物进行了比较。结果表明微球印迹聚合物具有更规则的形貌、对模板分子的吸附能力更强、均一性更好、比表面积更大、热稳定性更好。饱和吸附甲胺磷前后的印迹聚合物的红外光谱研究结果表明微球印迹聚合物中含有羧基功能基团并通过协同氢键作用特异性识别甲胺磷分子。固相萃取实验(MISPE)结果表明微球印迹聚合物对甲胺磷分子有较强的特异性识别。4.结合基质固相分散和加速溶剂萃取,建立了一种快速、灵敏、准确的测定复杂体系中有机氯农药多残留的分离分析新方法。以弗罗里硅土作为固相分散剂测定土壤中多种有机氯农药残留,回收率在77.4%-101.3%之间,检出限达到0.01-0.04ng/g;选用酸性氧化铝作为分散剂能有效去除鱼肉中脂类杂质,提取和净化一步完成,所得提取物干净可直接进行色谱分析。更多还原

【Abstract】 Organophosphorus pesticides(OPPs)and organochlorine pesticides(OCPs)are two classes of pesticides that are generally used for the control of a broad range of pests on cotton,rice,tobacco,sorghum,sugarcane and vegetables.The selective extraction/clean-up and determination of OPPs and OCPs in soils,water and foods has received considerable attention in recent years.Molecularly imprinting technique(MIT)is an emerging interdisciplinary methodology of molecular recognition that is developing in recent years.Molecularly imprinted polymers(MIPs)can discriminate template molecule and related analogs selectively.Because of their good affinity,sensitivity and stability,MIPs have been rapidly developed and used extensively in biotechnology,environmental monitoring, inartificial drugs,food industries and so on.During the process of matrix solid-phase dispersion(MSPD),the dispersant and sample is blended fully.The dispersant is an abrasive,producing shearing and grinding forces that induced disruption of the sample architecture,and accomplishing complete sample disruption and dispersion, the extraction and clean-up are achieved in one-step.Accelerated solvent extraction (ASE)is one of the latest techniques developed for extraction of solid/semi-solid samples.ASE operates at high temperatures(40-200℃)and high pressures (1000-2500psi),and allows faster extraction of analytes and requires only small volume of solvents.In this dissertation,molecularly imprinted polymers were synthesized with methamidophos(MAP)and acephate(APA)as template respectively.The interaction mechanisms between the template and the monomers were researched thoroughly by spectroscopy methods.The appearance,molecular affinity ability and specificity recognition characteristics of these MIPs were studied by physical and chemical methods.Selecting a right dispersant,a new method of selective extraction and clean-up of OCPs in complicated samples was developed by combining MSPD and ASE.The main work of this thesis is summarized as follows: 1.Molecular imprinting was used to develop a method based on noncovalent interaction for the synthesis of a MAP-specific polymer.The mechanism and selective binding characteristics of the imprinted polymer were evaluated by ~1H NMR,FT-IR and UV spectrometry.The results illustrated the interaction should be cooperative hydrogen bonds produced by self-assembling of the template and monomers.The stoichiometric mole ratio of MAP-methacrylic acid complex is 1:2.The Freundlich isotherm(FI)illustrated the MIP had better affinity capacity for MAP.The specificity of MIP for MAP was studied by FT-IR.The results illustrated that there were carboxyl in MIP combined with the template by cooperative hydrogen bonds.The hydrogen atom of NH and oxygen atom of P=O in MAP molecular would be the hydrogen-bonding sites with carboxyl.The results of molecularly imprinted solid-phase extraction(MISPE)also showed the specificity of MIP for MAP.The high affinity of the MIP to MAP could be applied in fast preconcentration,clean-up and determination of MAP in soil and water samples.2.Relative to MAP(pK_a=10.0),the basicity(pK_a=8.5)and toxicity Of APA are all weaker.Molecular imprinting was used to develop a method based on noncovalent interaction for the synthesis of a new MIP using APA as the template.The mechanism and selective binding characteristics of the imprinted polymer were evaluated by ~1H NMR、FT-IR and UV spectrometry.The results illustrated the interaction should be cooperative hydrogen bonds produced by self-assembling of the template and monomers.The stoichiometric mole ratio of APA-methacrylic acid complex is 1:2. The results of single-analyte binding assay showed the MIP had better affinity capacity for APA and smaller MAR The results of MISPE showed the specificity of MIP for APA and MAP.The high affinity of the MIP to APA and MAP could be applied to fast preconcentration,clean-up and determination of APA and MAP simultaneously.3.A 3.5μm diameter of microspheric molecularly imprinted polymer(MIP)was synthesized by precipitation polymerization.The shape,adsorption capability,thermal stability and porosity of microspheric MIP were compared with the bulk MIP.The microspheric MIP owned regular shape,stronger affinity capability,the more surface area,porosity and better thermal stability.The specificity of microspheric MIP for MAP was studied by FT-IR.The results illustrated that there were carboxyl in microspheric MIP combined with the template by cooperative hydrogen bonds.The results of MISPE also showed the specificity of microspheric MIP for MAP.4.The matrix solid-phase dispersion(MSPD)and accelerated solvent extraction(ASE) were combined to develop a fast,sensitive and accurate method for the determination of organochlorine pesticides(OCPs)in complicated samples.The Florisil was used as dispersant for the determination of 16 OCPs in soils.The recoveries were from 77.4% to 101.3%,and the limit of determination(LOD)were from 0.01 to 0.04 ng/g.The acid alumina was used as dispersant to adsorb the fat for the determination of OCPs in fish.The extraction and clean-up were completed in one-step.The extracts were clean enough to GC-ECD and GC-MS(SIM)analysis,nonother clean-up step was needed.更多还原