二乙基（3-甲基脲）（苯基）甲基磷酸酯（DEP）分子印迹聚合物的制备及其性能评价

【作者】 徐云；

【导师】 朱必学； 潘灿平；

【作者基本信息】 贵州大学 ， 物理化学， 2009， 硕士

【摘要】 分子印迹聚合物（MIPs）由于对模板分子具有“记忆”识别功能,具有专一性,且由于制备简单、低造价、稳定性好、可重复使用的优点,它在有机磷农药的残留检测上具有广阔的应用前景。当前在MIPs的制备和评价技术上存在着模板泄露这一问题。本文通过合成二乙基（3-甲基脲）（苯基）甲基磷酸酯（DEP）,以此为假模板采用沉淀聚合法来制备MIPs,考察了其特异吸附性能及作为假模板对结构类似有机磷的保留识别性能。1、通过Material studio软件进行计算机模拟筛选出了几个较优功能单体和交联剂。2、在计算机模拟的基础上通过一系列的吸附和核磁实验,选出了一个最优印迹条件:甲基丙烯酸（MAA）为功能单体,交联剂为乙二醇二甲基丙烯酸酯（EDMA）,所用比例为DEP:MAA:EDMA=1:9:45,溶剂为三氯甲烷。3、等温吸附实验表明MIPs对DEP的吸附量大约是空白聚合物（NIPs）的两倍。Scatchard数据拟合发现MIPs主要存在两种不同亲和力的作用位点,高亲和力位点的最大表观结合常数Q₍max₌1.31/μmol/g,离解常数K_d=0.5 mmol/L,低亲和力位点的最大表观结合常数Q_max=2.41/μmol/g,离解常数K_d=26 mmol/L。4、印迹材料对其结构类似物的选择吸附效果表明,与其它的农药分子相比较,含有N-H基团的有机磷小分子农药甲胺磷和乙酰甲胺磷有较好的印迹效果。5、色谱保留实验表明,在DEP与8种农药（包括6种有机磷农药）中,对含有N-H基团的甲胺磷和乙酰甲胺磷有较大的保留能力。可以为将来更好地将MIPs材料用作液相色谱或固相萃取填料来对含有N-H基团的有机磷农药进行分离和富集提供了很好的理论基础和实践经验,从而提高分析鉴定的准确性。6、通过物性表征发现MIPs、NIPs都具有良好的热稳定性,分解温度都高于210℃;电镜扫描显示,印迹聚合物呈微球状颗粒,其粒径在1.8 um～2.5 um,可以将此MIPs印迹微球用作高效液相色谱中快速分离的一种吸附材料。更多还原

【Abstract】 Molecularly-Imprinted Polymers(MIPs) is the material which has the function of remembrance and recognition for template,and it has the merits of simple in preparation, cheaply making,steady in performance and also repeated use.Therefore,MIPs can be widely used in detection the organophosphorus pesticides residues.Recently,MIPs mostly be synthesized by using the targete molecules as template, and the template can happen leak out of the polymer and interferes in the following analysis.In this paper,by synthesis diethyl(3-methylureido)(phenyl) methylphosphonate(DEP),we prapared the MIPs by precipitation polymerization using DEP as dummy template to study it’s specific affinity and also the ability to recognize a series of pesticides,which are the structural analogues of DEP and mostly belong to organophosphorus pesticides.1、Based on the computer simulation and by doing series NMR and adsorb experiments,we selected a best imprinting condition:DEP as dummy template, methacrylic acid(MAA),ethyleneglycol dimethacrylate(EDMA) and chloroform as functional monomer,cross-linker and porogen,respectively,and the ratios of the DEP:MAA:EDMA=1:9:45.2、Equilibrium rebinding experiments indicated that the adsorption capacity of MIPs for DEP is two times of control polymer(NIPs).Scatchard plot of analysis revealed that there was two classes binding sites populated in the imprinted polymer with dissociation constants of 0.5mmol/L for high affinity sites and 26 mmol/L for low affinity sites,an apparent maximum binding constant of 1.31μmol/g for high affinity sites and 2.41μmol/g for low affinity sites.3、Binding selectivity shows that MIPs exhibited better selectivity and recognizability for methamidophos and orthene which contain N-H group compared with other pesticides.4、Liquid chromatographic analysis of the DEP and eight pesticides(including six organophosphorus pesticides) indicated that MIPs showed better reserved capability for methamidophos and orthene which contain N-H group compared with other pesticides.It is hoped that such MIPs material would be used as stuff being packed in liquid chromatographic column and solid phase extrated column.And it will improve the veracity of test results.5、The thermal properties were studied by TG and their thermal decomposition temperatures were above 210℃;The SEM showed that the MIPs are microspheres and the diameters are about 1.8um～2.5um which may be used as affinity material for high speed separation in HPLC.更多还原