土壤中手性环境污染物的分离及其对映体选择性降解研究

【作者】 韩莉；

【导师】 鲁晓明； 林金明；

【作者基本信息】 首都师范大学 ， 物理化学， 2009， 硕士

【摘要】 近年来,手性农药的对映体的分离及对映体选择性降解行为研究,一直是环境化学研究的热点之一。建立简便、快捷、准确、灵敏的对映体分离分析方法具有非常重要的学术意义和应用价值。由于手性农药的生物活性存在显著的立体特异性,其活性往往只存在于一个或少数几个异构体中。目前绝大多数手性农药仍然作为外消旋体生产和使用,在对映体水平上研究手性农药的环境行为有着重要的理论和实际应用价值。本研究围绕着农药的手性分离、提纯和对映体选择性降解开展相关研究。本论文共分为四章,分述如下:第一章介绍了手性环境污染物的研究历史,研究方法、影响手性环境污染物对应体选择性降解的因素和最新进展,以阐述本论文的目的和意义。第二章以毛细管电泳法,通过添加手性选择剂,成功分离了手性农药咪唑乙烟酸对映体。本章以羟丙基-β-环糊精(HP-β-CD)为手性选择剂,对咪唑乙烟酸对映体进行手性拆分,实验考察了手性添加剂种类、缓冲溶液pH值、手性添加剂浓度、堆积效应的影响;并就拆分机理进行了初步探讨。第三章应用毛细管电泳法分析环境土样中咪唑乙烟酸手性对映体进行分析检测,并研究了咪唑乙烟酸的对映体选择性降解情况。对大豆田中的咪唑乙烟酸对映体经行了为期30天的实时监测。咪唑乙烟酸对映体的对映体比率由最初的0.97变为0.58。实验结果表明,咪唑乙烟酸对映体在狗尾草的土壤环境中有选择性降解差异,存在生物活性差异。咪唑乙烟酸的对映体咪唑乙烟酸-I比咪唑乙烟酸-II比的降解速率要快的多,在土壤中的降解半衰期分别为6.8天和7.4天。本实验还从动力学角度对咪唑乙烟酸对映体的降解行为做了进一步研究,探讨了导致咪唑乙烟酸对映体降解差异的可能原因。第四章采用表面分子印迹技术合成了对除草剂咪唑乙烟酸具有较好选择性的表面分子印迹聚合物(MIP)。用IR和SEM测试技术分别对表面印迹聚合物进行了结构表征和表面形貌观察;静态吸附平衡实验和Scatchard分析结果表明,该印迹聚合物中存在着2类不同的结合位点。与化学组成相同的非印迹聚合物(NIP)相比,MIP对咪唑乙烟酸有较高的选择性和吸附性。更多还原

【Abstract】 Chiral separation and enantioselective degradation of chiral pesticides become an important and fascinating research field in environment chemistry. It has momentous academic and practice significance to develop simple, fast, sensitive methods for the separation of the enantiomers. Many pesticides are chiral compounds and consist of two or more stereoisomers, which might differ in biological activity, toxicity on beneficial and non-target organisms, and environmental fate. Thus, it is necessary to obtain information on the toxicity and biotransformation of the chiral pollutants by developing a suitable method for the chiral resolution of the environmental pollutants. The dissertation consists of for chapters.Chapter 1 The enantioselective degradation of chiral environment pollution was reviewed. The objective and significance of this dissertation were described in brief.Chapter 2 The method for the separation of imazethapyer enantiomers was developed by using hydroxypropyl-β-cyclodextrin-modified modified capillary electrophoresis. The types and concentration of the chiral selectors, pH were investigated.Chapter 3 Enantioselective degradation of imazethapyer in field soil was investigated by capillary electrophoresis. The enantiomeric ratio values of the two enantiomeric pairs changed from initial about 0.97 to 0.58, respectively. As for enantioselective analysis, the two enantiomers were degraded with half-lives of 6.8 and 7.4 days respectively, indicating an obvious enantioselectivity.Chapter 4 A molecular imprinting polymer (MIP) using imazethapyer as temp late molecule synthesized on the surface of silica. The MIP was characterized by IR spectroscopy and SEM. The static adsorption equilibrium experiments and the Scatchard analysis show that there were two kinds of binding sites. The MIP exhibited better adsorption properties and selectivity compared with the corresponding non-imprinted polymers.更多还原