林可霉素分子印迹聚合物的制备及吸附性能研究

以林可霉素(LIN)为模板,利用分子模拟方法模拟丙烯酰胺(AM)、甲基丙烯酸(MAA)、2-乙烯基吡啶(2-VP)和4-乙烯基吡啶(4-VP)4种常见的功能单体与模板分子的结合能,结果表明4-VP结合能最强为-98.25 kJ/mol。用悬浮聚合法制备林可霉素分子印迹聚合物(MIP)并对其性能进行评价。使用气相色谱检测各功能单体制备的印迹聚合物的吸附量,结果4-VP制备的印迹聚合物吸附量最大为102.8μmol/g,分子模拟结果与吸附试验结果一致,表明分子模拟可以为功能单体选择提供依据。采用静态吸附试验和动态吸附试验对印迹聚合物吸附性能表征,并进行了Scatchard模型分析。结果印迹因子为2.54,并且在150 min内较快地达到吸附平衡,表明林可霉素分子印迹聚合物具有较高的选择吸附性,可用于林可霉素的富集。     

基于活性自由基聚合的槲皮素分子印迹聚合物的合成及在维药祖卡木颗粒活性成分分析中的应用

以二苄基三硫代碳酸酯(DBTTC)为可逆加成-断裂链转移剂(RAFT试剂),槲皮素(Quercetin)为印迹化合物,分别以甲基丙烯酸(MAA)、丙烯酰胺(AM)、丙烯酸(AA)、4-乙烯基吡啶(4-VP)和2-乙烯基吡啶(2-VP)作为功能单体,利用可逆加成-断裂链转移自由基聚合法制备了槲皮素分子印迹聚合物.实验考察了不同的制备条件,利用氮吸附测试及扫描电子显微镜对聚合物的结构进行了测定,采用色谱法对印迹聚合物的识别能力及分离效率进行了评价.研究了聚合条件-聚合物结构-分离效率的关系,探讨了利用活性自由基合成分子印迹聚合物的方法及特点;并将合成的分子印迹聚合物用作固定相,对维药祖卡木颗粒中的槲皮素进行了分离富集.研究结果表明,通过活性自由基聚合法合成的分子印迹聚合物具有更好的形态结构,对目标分子具有很好的吸附效率.     

不同功能单体合成的分子印迹聚合物识别性能的研究

采用分子印迹技术,用不同的功能单体合成了槲皮素的分子印迹聚合物,测定了它们的吸附性能,并考察了模板分子与功能单体相互作用与印迹聚合物吸附性能的关系。结果表明:在四氢呋喃-氯仿(V/V 8:2)的溶剂体系中以2-乙烯基吡啶(2-VP)为功能单体合成的分子印迹聚合物的吸附性能最强,吸附量为4457.52(μg)/g,通过紫外光谱法测定的结果,在该条件下槲皮素与2-乙烯基吡啶的作用力也是较强的。     

香豆素分子模板聚合物的合成与性能研究

以香豆素为模板分子, α-甲基丙烯酸(MAA)、丙烯酰胺(MA)、2-乙烯基吡啶(2-VP)和4-乙烯基吡啶(4-VP)为功能单体, 二甲基丙烯酸乙二醇酯(EGDMA)为交联剂, 利用分子模板技术分别在甲苯、甲醇、氯仿和乙腈溶剂中合成了一系列香豆素分子模板聚合物(MTP), 研究了聚合体系组成对模板聚合物吸附特性的影响. 结果表明, 在所合成的模板聚合物中, 以MAA为功能单体, 乙腈为致孔溶剂, 以1∶4∶30的摩尔比加入模板分子、MAA及EGDMA时制备的模板聚合物吸附容量高、印迹效果和选择性好. 此模板聚合物有作为白芷样品中香豆素吸附分离材料的应用前景.     

沉淀聚合制备诺氟沙星-Zn2+分子印迹聚合物及其印迹方式的研究

采用沉淀聚合的方式以诺氟沙星(NFA)-Zn2+为模板分子,乙二醇二甲基丙烯酸酯为交联剂,分别选取酸性功能单体甲基丙烯酸与碱性功能单体4-乙烯基吡啶制备了诺氟沙星-Zn2+的分子印迹聚合物.通过紫外光谱研究发现诺氟沙星与Zn2+及两种功能单体均发生了金属配位印迹作用且形成了比例不同的印迹复合物.红外光谱的功能基团的表征结果显示,甲基丙烯酸与诺氟沙星-Zn2+形成了以诱导作用占优的三元配合物,而4-乙烯基吡啶则与诺氟沙星-Zn2+形成了共轭作用占优的三元配合物.扫描电镜及粒径分布实验表征了聚合物的物理特性,结果显示印迹聚合物的表面存在孔及孔道结构而非印迹聚合物的表面较致密不存在孔且制备的印迹聚合物的粒径均在100μm以下,其平均粒径为39μm.等温结合及选择性实验的结果表明4-乙烯基吡啶为功能单体制备的印迹聚合物的选择性识别性能优于甲基丙烯酸为功能单体制备的印迹聚合物,其特异性吸附容量和印迹指数分别为66.84μmol/g和4.207.同时在混合溶液的选择性实验中以4-乙烯基吡啶(4-VP)为功能单体制备的印迹聚合物的选择识别诺氟沙星的能力优于以甲基丙烯酸为功能单体的聚合物,其识别因子分别为3.408和2.909,而非印迹聚合物对底物的吸附量较小且识别因子均接近于1,说明非印迹聚合物对底物的识别为非选择性的.     

绿原酸分子印迹体系的计算模拟及复合膜的制备

以绿原酸为模板分子, 以丙烯酰胺(AM)、丙烯酸(AA)、4-乙烯基吡啶(4-VP)、2-乙烯基吡啶(2-VP)四种物质分别作为功能单体, 使用密度泛函理论(DFT)方法和PM3半经验法, 运用Gaussian 03软件模拟模板分子与不同功能单体的分子印迹聚合物预组装体系的构型、能量及复合反应的结合能(ΔE), 以讨论不同功能单体对分子印迹聚合物识别性能的影响, 结果丙烯酰胺的印迹效应最好. 以聚偏氟乙烯微孔滤膜为支撑膜, 绿原酸为模板分子, AM, AA, 4-VP, 2-VP四种物质分别作为功能单体, 用紫外光引发表面修饰聚合制备了绿原酸分子印迹复合膜, 测量底物绿原酸在几种印迹膜上吸附量的大小, 得出的实验结论和理论计算的结果相一致. Scatchard 分析表明, 在所研究的浓度范围内分子印迹复合膜中存在两类不同性能的吸附位点, 结合位点的平衡离解常数K_d1和K_d2分别为0.151和0.480 mmol/L. 底物(绿原酸)的结合和渗透选择性实验表明, 分子印迹复合膜对绿原酸有较好的结合性能, 结合量分别是14.934和28.123 μmol/g.     

Synthesis of Norfloxacin-Zinc （II） Imprinted Polymer by Precipitation Polymerization and Study on Its Imprinting Form

采用沉淀聚合的方式以诺氟沙星（NFA）-Zn2＋为模板分子,乙二醇二甲基丙烯酸酯为交联剂,分别选取酸性功能单体甲基丙烯酸与碱性功能单体4-乙烯基吡啶制备了诺氟沙星-Zn2＋的分子印迹聚合物.通过紫外光谱研究发现诺氟沙星与Zn2＋及两种功能单体均发生了金属配位印迹作用且形成了比例不同的印迹复合物.红外光谱的功能基团的表征结果显示,甲基丙烯酸与诺氟沙星-Zn2＋形成了以诱导作用占优的三元配合物,而4-乙烯基吡啶则与诺氟沙星-Zn2＋形成了共轭作用占优的三元配合物.扫描电镜及粒径分布实验表征了聚合物的物理特性,结果显示印迹聚合物的表面存在孔及孔道结构而非印迹聚合物的表面较致密不存在孔且制备的印迹聚合物的粒径均在100μm以下,其平均粒径为39μm.等温结合及选择性实验的结果表明4-乙烯基吡啶为功能单体制备的印迹聚合物的选择性识别性能优于甲基丙烯酸为功能单体制备的印迹聚合物,其特异性吸附容量和印迹指数分别为66.84μmol/g和4.207.同时在混合溶液的选择性实验中以4-乙烯基吡啶（4-VP）为功能单体制备的印迹聚合物的选择识别诺氟沙星的能力优于以甲基丙烯酸为功能单体的聚合物,其识别因子分别为3.408和2.909,而非印迹聚合物对底物的吸附量较小且识别因子均接近于1,说明非印迹聚合物对底物的识别为非选择性的.     

染料木素分子印迹聚合物的制备及其识别性能

以染料木素为模板分子、4-乙烯基吡啶(4-VP)为功能单体、乙二醇二甲基双丙烯酸酯(EGDMA)为交联剂、四氢呋喃(THF)为溶剂,采用本体聚合法制备了染料木素的分子印迹聚合物;采用静态平衡结合实验研究了该分子印迹聚合物对染料木素的结合能力和选择性能.结果表明,与化学组成相同的相应非印迹聚合物相比,染料木素分子印迹聚合物对染料木素的吸附性能和选择性更好.利用所合成的分子印迹聚合物作为固相萃取材料填充固相萃取小柱,可以选择性地从豆奶粉中分离、富集染料木素;此外,该分子印迹聚合物还有望用于其他豆制品的分析检验.     

分子模拟辅助设计L-苯丙氨酸分子印迹聚合物及其性能研究

对L-苯丙氨酸(L-Phe)为模板分子、分别以氯化1-羧甲基-3-乙烯基咪唑离子液体([VIM]Cl)、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(EGDMA)为交联剂的分子印迹组装体系进行分子模拟分析、荧光光谱分析,预测较优功能单体,辅助设计了L-苯丙氨酸分子印迹聚合物(L-MIPs);其次,通过实验系统研究了功能单体种类对L-MIPs的吸附性能和印迹因子的影响,并比较了分别以[VIM]Cl、MAA和4-VP为功能单体制备的L-苯丙氨酸印迹聚合物的吸附行为,运用多种表征方法对L-MIPs形貌、表面元素组成、热稳定性进行了研究。结果表明以[VIM]Cl为最优功能单体,且制备的聚合物在300 °C内具有较好的热稳定性,在浓度为1.0 mg.mL_-1,饱和吸附量可达33 mg.g_-1,印迹因子可达3.86。相对于结构类似物D-Phe、L-His或L-Trp,识别因子β分别达到1.24,1.41和1.30。因此,采用计算机模拟的方法对于分子印迹体系的中功能单体的筛选及分子印迹聚合物性能的预测有重要的意义。     

沉淀制备双酚Aπ-π堆积自组装印迹聚合物及其特异性识别机理研究

以类雌性激素双酚A为模板分子,选取4-乙烯基吡啶作为功能单体,在极性溶剂甲醇中,通过非共价键完成自组装过程,沉淀聚合制备对双酚A分子具有高度选择性识别和亲和力的分子印迹聚合物.采用紫外-可见光谱研究了双酚A和4-乙烯基吡啶的配合方式以及配位比,结果表明双酚A与4-乙烯基吡啶以配位比1∶2的方式,在极性溶剂中,无法以常用的氢键形成超分子配合物,却可以π-π堆积这种非共价键完成自组装过程.通过红外谱图,验证了沉淀聚合法制备的印迹聚合物可以完成双酚A的印迹和可逆分离.通过扫描电镜和等温吸附实验考察了分子印迹聚合物对模板分子的特异性识别和选择性吸附机理,印迹聚合物的特异性吸附容量为37.39μmol/g,印迹指数为4.31;对其结构类似物四溴双酚A和苯酚的分离因子分别为2.51和2.06,同时对莠去津,萘普生和槲皮素的分离因子分别为2.14,2.26和2.63,证实了分子印迹聚合物在极性溶剂中可以对双酚A分子进行很好的特异性识别,并且识别环境更接近天然分子环境.     

N,N′-亚甲基双丙烯酰胺与4-乙烯基吡啶共聚微凝胶的γ-射线辐照合成

通过γ 射线辐照技术 ,在稀水溶液中实现了N ,N′ 亚甲基双丙烯酰胺 (Bis)与 4 乙烯基吡啶 (4 VP)的无皂乳液共聚 ,得到平均流体力学半径 (Rh)为 5 6～ 15 2nm的一系列微凝胶 ,并通过红外光谱、热分析、透射电镜进行了表征 .通过测定Rh、吸光度、凝胶比 ,研究了与Bis共聚的单体及比例、剂量和剂量率对微凝胶合成的影响 .结果表明 ,微凝胶的大小可以通过吸收剂量、单体相对含量的改变来进行控制 .最后 ,对微凝胶的形成机理进行了初步探讨 .     

Effects of metal salts on polymerization. Part VII. Radical polymerization and spectra of vinylpyridine in the presence of cobaltous chloride

The radical polymerizability of vinylpyridines in the presence of cobaltous chloride was studied in DMF solution, and the results were correlated with the spectroscopic data obtained for methanol solution. In general, the behavior of vinylpyridine complexed with cobaltous chloride is qualitatively the same as that of zinc complexes reported previously. The rates of polymerization were enhanced by the addition of cobaltous chloride when 4-vinylpyridine(4-VP) or 2-methyl-5-vinylpyridine(MVP) was the monomer, whereas the polymerization of 2-vinylpyridine(2-VP) was retarded by cobaltous chloride. The monomer reactivity of all the vinylpyridines was also enhanced by complex formation as studied by copolymerization with styrene. The enhancement of reactivity of 4-VP complexed with cobaltous chloride is somewhat smaller than that of the corresponding zinc complex.     

On-line solid-phase extraction with molecularly imprinted polymers to selectively extract substituted 4-chlorophenols and 4-nitrophenol from water

Three polymers have been synthesised using 4-chlorophenol (4-CP) as the template, following different protocols (non-covalent and semi-covalent) and using different functional co-monomers, 4-vinylpyridine (4-VP) and methacrylic acid (MAA). The polymers were evaluated to check their selectivity as molecularly imprinted polymers (MIPs) in solid-phase extraction (SPE) coupled on-line to liquid chromatography. The solid-phase extraction procedure using MIPs (MISPE), including the clean-up step to remove any interferences, was optimised. The 4-VP non-covalent polymer was the only one which showed a clear imprint effect. This MIP also showed cross-reactivity for the 4-chloro-substituted phenols and for 4-nitrophenol (4-NP) from a mixture containing the 11 priority EPA (Environmental Protection Agency) phenolic compounds and 4-chlorophenol. The MIP was applied to selectively extract the 4-chloro-substituted compounds and 4-NP from river water samples.     

Preparation of organic-inorganic composite anion-exchange membranes via aqueous dispersion polymerization and their characterization

Organic-inorganic composite membranes based on poly(vinyl alcohol)/SiO(2) were prepared via an aqueous dispersion polymerization route and anion-exchange groups were introduced in the membrane matrix by the chemical grafting of 4-vinylpyridine with the desired content. These membranes were extensively characterized for their surface morphology, thermal stability, water content, and surface-charge properties using SEM, TEM, FTIR, TGA, water uptake, and ion-exchange capacity measurements. Counterion transport numbers across these membranes were estimated from membrane potential data. Membrane conductance measurements were also performed and these data were used for the estimation of values of counterion diffusion coefficients in the membrane phase. Physicochemical and electrochemical properties of these membranes and equivalent pore radius (estimated from electroosmotic flux measurements) were found to be highly dependent on the 4-vinylpyridine (4-VP) content in the membrane phase. It was also observed that for better selectivity and membrane conductivity of anion-exchange membranes complete optimization of the loading of 4-VP in the membrane phase is necessary. Furthermore, among these, membrane with 25% loading with 4-VP exhibited very good selectivity, water content, and ion-exchange capacity along with moderate membrane conductivity, which may be used for their application in electro-driven separation at elevated temperatures or for other electrochemical processes.     

A VERSATILE AND REGIOSELECTIVE SYNTHESIS OF VICINAL AZIDOALCOHOLS USING CROSS-LINKED POLY（4-VINYLPYRIDINE） SUPPORTED AZIDE ION UNDER SOLVENT-FREE CONDITIONS

A new polymeric reagent, cross-linked poly（4-vinylpyridine） supported azide ion, [P4-VP]N3, was introduced as polymeric reagents for efficient and regioselective conversion of epoxides to azidohydrins in the presence of cross-linked poly（4-vinylpyridine） supported sulfuric acid, [P4-VP]H2SO4, as a solid proton source and as catalyst under solvent-free conditions. The advantages of this polymeric reagent over some of those reported in the literature are easy work-up procedure and regeneration of the reagent.     

Graft Copolymerization of 4-Vinylpyridine Onto Partially Carboxymethylated Cellulose. the Degree of Substitution Effect

The graft copolymerization of 4-vinylpyridine (4-VP) onto partially car-boxymethylated cotton (PCMC), having different carboxymethyl contents, was investigated. Under similar reaction conditions, both the graft yield and eerie ion consumption increased by increasing the degree of substitution of carboxymethyl groups of PCMC up to a value of 0.11, beyond which grafting and Ce(IV) consumption decreased. Proof for grafting onto PCMC was provided through IR analysis. the eerie salt-initiated polymerization of 4-VP in the absence of PCMC was also studied. Three series of homo-polymerization reactions of 4-VP directly initiated by eerie ammonium nitrate were carried out with varying reaction times. Each series was run at a different nitric acid concentration. Both conversion and eerie ion consumption, as well as molecular weight, increased with reaction time. Increasing the nitric acid concentration increased both conversion and eerie ion consumption while the molecular weight decreased.     

Polymerization of 4-vinylpyridine with acylating agents

The reaction of 4-vinylpyridine (4-VP) with acylating agents in diethyl ether was investigated. Acetyl chloride (AcCl) and trifluoroacetic anhydride [(TFAc)₂O] yield colored oligomers with 4-VP, denoted P-4VP—AcCl (III) and P-4VP—(TFAc)₂O (IV). Nuclear magnetic resonance spectrometry was used to analyze these products. A structure (XII), representing a random copolymer resulting from 1,2-polyaddition and 1,6-polyaddition to 4-VP, is proposed for III and IV. Alternative mechanisms which explain these observations are discussed. Acetic anhydride (Ac₂O) does not acylate 4-VP. It is proposed that this result is caused by the inability of Ac₂O to quaternize 4-VP as an initial step leading to polymerization.     

Binding properties of 2,4,5-trichlorophenoxyacetic acid-imprinted polymers prepared with different molar ratios between template and functional monomer

Several molecularly-imprinted polymers binding the herbicide 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) were prepared with a molar ratio between the functional monomer and the template molecule in the pre-polymerisation mixture set between 1+2 and 20+1. The functional monomer used was 4-vinylpyridine (4-VP), the cross-linker was ethylene dimethacrylate, and the porogenic solvent was a mixture of methanol–water 3+1 (v/v). The polymers obtained were grinded, sieved and packed in 100 mm×3.9 mm HPLC columns. The effects of the mobile phase composition were evaluated by eluting the columns with acetonitrile–water mixtures. The results obtained indicate that column capacity, selectivity factor and the imprinting effect are controlled by ion-pair and hydrophobic interactions between the analyte and the stationary phase. In the full range of ratios considered, column capacity, selectivity factor and imprinting effect are inversely proportional to the molar ratio between the template molecule and the functional monomer.     

A computational model for selectivity evaluation of 2-(3,4-dimethoxyphenyl)ethylamine (homoveratrylamine) imprinted polymers towards biogenic compounds

A computational model was proposed to evaluate the affinity and selectivity of 2-(3,4-dimethoxyphenyl)ethylamine (homoveratrylamine) imprinted polymers. Four functional monomers: methacrylic acid, 1-vinylimidazole, 4-vinylpyridine, and allylamine were taken into account. Two dielectric constants were used for solvent simulations: a value of ?=2.38r(ij) for toluene was used in the analysis of prepolymerization complexes, and a value of ?=36r(ij) for methanol-water was used in the investigations of adsorption. Theoretical analysis predicted the highest affinity for the polymer synthesized from methacrylic acid. Experimental results confirmed the finding. The prepolymerization complex formed by homoveratrylamine and four methacrylic acid molecules was used to design the polymer cavity. The selectivity of the polymer was analyzed as a simulation of adsorption of six compounds in the cavity by docking procedure. Selected compounds are structurally related to the template or can be present in biological samples. The designed polymer has high selectivity towards homoveratrylamine. The proposed computational procedure could be used for successful evaluation of the imprinted polymers.