以分子印迹聚合物为固定相手性拆分1,1′-联-2-萘酚及其衍生物

以(R)-(+)-1,1′-联-2-萘酚为模板分子,4-乙烯基吡啶为功能单体合成了分子印迹聚合物,将其作为高效液相色谱的固定相,研究其手性识别特性。对该固定相的手性拆分的色谱条件进行了优化。实验结果表明,合成的印迹聚合物对(R)-(+)-1,1′-联-2-萘酚具有较强的亲和力和特定的选择性,能有效拆分1,1′-联-2-萘酚对映体,分离因子最高达到12.25。通过优化色谱条件,该分子印迹聚合物还能对与1,1′-联-2-萘酚结构相似的衍生物5,6,7,8,5′,6′,7′,8′-八氢-1,1′-联-2-萘酚和1,1′-联萘-2-氨基-2′-酚进行手性拆分,分离因子分别达到1.51和2.40。     

电沉积硅烷分子印迹膜修饰电极的制备及其应用

以3,4-二羟基苯甲酸作模板分子,在玻碳电极表面恒电位沉积四甲氧基硅烷和苯基三甲氧基硅烷,经无水乙醇将模板分子洗脱,制得硅溶胶-凝胶分子印迹膜电极.该电极能有效地抑制电化学氧化过程中3,4-二羟基苯甲酸的电聚合及其同分异构体2,4-二羟基苯甲酸对测定的干扰.实验表明,该修饰电极对3,4-二羟基苯甲酸测定的线性浓度范围为1.0×10-5~8.0×10-4mol.L-1,浓度检测下限为5.0×10-6mol.L-1.     

Effect of matrix polymerization conditions on the structure and adsorption properties of porous polymers on the basis of divinylbenzene,acrylonitrile, and methyl methacrylate

A comparative study was carried out on the matrix polymerization of divinylbenzene, acrylonitrile, and methyl methacrylate in SBA-15 silica mesoporous molecular sieves. The occupancy of the matrix mesopores by the starting monomer, the medium, the polymerization temperature and time as well as the means of removing the exotemplate were all found to affect the spatial organization and porous structure of the polymer materials. Surplus occupancy of the mesopores by the monomer (1–1.5), polymerization in vacuum, and an alkaline method for matrix removal were found to be optimal. IR spectroscopy was used to find the conversion of the starting polymer by following the relative change in intensity of the vinyl group bands. Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 44, No. 6, pp. 371–375, November–December, 2008.     

Evaluation of a molecularly imprinted polymer for the isolation/enrichment of β-estradiol

The selective preconcentration of estradiol was explored using the recognition ability of a molecularly imprinted polymer (MIP) in the solid phase extraction (SPE) format. Polymeric particles were imprinted with 17β-estradiol using methacrylic acid as functional monomer and divinylbenzene as crosslinker. Binding studies of these polymeric particles towards 17β-estradiol showed selectivity over non-imprinted polymers, using acetonitrile as solvent. The imprinted polymer showed a recovery of 88% for β-estradiol in deionized water and 81% in surface water. The selectivity of the MIP over the non-imprinted polymer was relatively low, only 10% higher recovery. The results indicate that the MIP imprinted with 17β-estradiol does not appear to provide a viable approach to be used in a sample clean-up or enrichment step for the determination of estradiol in aqueous systems.     

Preparation of an open-tubular capillary column with a monolithic layer of S-ketoprofen imprinted and 4-styrenesulfonic acid incorporated polymer and its enhanced chiral separation performance in capillary electrochromatography

Enhanced chiral separation performance has been observed for ketoprofen enantiomers in capillary electrochromatography (CEC) with an open-tubular (OT) column prepared with a specific molecule imprinted polymer (MIP) on the innerwall of 50mum ID capillary. The column was prepared by in situ thermal polymerization inside the pretreated and silanized fused silica capillary. A specific diluted monomer mixture composed of S-ketoprofen, methacrylic acid (MAA, functional monomer), ethylene glycol dimethacrylate (EDMA, cross-linker), and 4-styrenesulfonic acid (4-SSA) dissolved in 9/1 (v/v) acetonitrile/2-propanol was used to fabricate the OT-MIP layer. 4-SSA was added to form a MIP layer capable of stable and strong electro-osmotic flow (EOF) over the pH range of this study securing CEC elution of ketoprofen having partial negative charge near the optimized pH. Various parameters such as buffer pH, organic modifier composition, salt concentration, and applied potential have been optimized for CEC chiral separation of ketoprofen enantiomers. Very good separation selectivity and efficiency were observed, thus the chromatographic resolution of ketoprofen enantiomers was as high as 10.5, and the number of theoretical plates of R-ketoprofen, 156,000/m (40,000/m for S-ketoprofen), which proves that the OT-MIP-CEC type approach is a promising strategy in MIP study.     

分子印迹样品前处理技术的研究进展

样品前处理是分析过程的关键环节,直接影响着分析结果的准确度和精密度．分子印迹聚合物具有特异性识别能力,能从复杂样品中选择性分离富集目标物,在复杂样品前处理领域中有重要的发展潜力和应用前景．本文综述了近年来分子印迹样品前处理技术的研究进展,包括分子印迹固相萃取、分子印迹固相微萃取、分子印迹膜萃取等样品前处理技术．     

基于MCM-41分子筛表面的镱离子印迹聚合物的制备及其性能

运用离子印迹技术,以3-氯丙基三乙氧基硅烷为锚定剂,将功能单体直链聚乙烯亚胺(PEI)接枝在MCM-41分子筛表面,选择镱离子作为模板离子,以环氧氯丙烷交联制备出基于MCM-41表面的镱离子印迹聚合物Yb(Ⅲ)-IIP-PEI/MCM-41,并以同样的方法制备非离子印迹聚合物(NIP-PEI/MCM-41)。 利用傅里叶变换红外光谱仪和扫描电子显微镜等技术手段对Yb³⁺印迹聚合物进行表征,采用静态吸附法确定了Yb(Ⅲ)-IIP-PEI/MCM-41对Yb³⁺的最佳吸附条件及选择性吸附性能。 结果表明,Yb(Ⅲ)-IIP-PEI/MCM-41和NIP-PEI/MCM-41的最大吸附量分别为229.93和99.27 mg/g;印迹材料对Yb³⁺的吸附符合Langmuir模型;吸附平衡在40 min的时候基本可以达到,可以利用准二级动力学模型来描述其吸附过程;Yb(Ⅲ)-IIP-PEI/MCM-41对Yb³⁺具有较强的选择性,同时也具有很好的重复使用性能。 成功地将MCM-41和离子印迹聚合物的优点结合起来,制备出一种对稀土Yb离子既有高吸附量又有高选择性的吸附材料,为进一步将其应用在处理实际废水,分离回收低浓度稀土废水中的稀土元素等方面打下了基础。     

Synthesis of a molecularly imprinted polymer on mSiO2@Fe3O4 for the selective adsorption of atrazine

Atrazine contamination of water is of considerable concern because of the potential hazard to human health. In this study, a magnetic molecularly imprinted polymer for atrazine was prepared by the surface‐imprinting technique using Fe₃O₄ as the core, mesoporous silica as the carrier, atrazine as the template, and itaconic acid as the functional monomer. The magnetic molecularly imprinted polymer was characterized by Fourier‐transform infrared spectroscopy, scanning electron microscopy, X‐ray diffraction, and vibration‐sample magnetometry. The binding properties of the magnetic molecularly imprinted polymer toward atrazine were investigated by adsorption isotherms, kinetics, and competitive adsorption. It was found that the adsorption equilibrium was achieved within 2 h, the maximum adsorption capacity of atrazine was 8.8 μmol/g, and the adsorption process could be well described by the Langmuir isotherm model and pseudo‐second‐order kinetic model. The magnetic molecularly imprinted polymer exhibited good adsorption selectivity for atrazine with respect to structural analogues, such as cyanazine, simetryne, and prometryn. The reusability of the magnetic molecularly imprinted polymer was demonstrated for at least five repeated cycles without a significant decrease in adsorption capacity. These results suggested that the magnetic molecularly imprinted polymer could be used as an efficient material for the selective adsorption and removal of atrazine from water samples.     

Molecular Recognition Ability of Molecularly Imprinted Polymer Nano- and Micro-Particles by Reversible Addition-Fragmentation Chain Transfer Polymerization

The role of molecularly imprinted polymers (MIPs) is changing from academic to applied researches. Challenging problems about MIP will be more highlighted in applicable uses and solving these problems is vital. The controlled/“living” radical polymerization (CLRP) techniques are applicable to solve the challenging problems in MIPs. The “living” nature of CLRP helps to improve the heterogeneity of binding sites in MIPs as a main challenge where precise control over sizes, compositions, and surface functionalities is achieved. Among different techniques of CLRP, reversible addition-fragmentation chain transfer (RAFT) technique presents distinguished benefits such as compatibility and tolerance to a wide range of functional monomers and mild reaction conditions rather than other CLRP techniques. In this review, in order to obtain more insights into the potential benefits of RAFT polymerization in fabrication of nano and micro MIP networks, recent research in advanced MIP materials for different templates with improved morphology, efficiency, and binding capacities with respect to traditional free radical polymerization (FRP) will be discussed. MIPs prepared via RAFT method have advantages of MIPs as high performance molecular recognition devices and CLRP as controllable polymerization mechanism, simultaneously.     

Influence of Structural Features on the Cellular Uptake Behavior of Non‐Targeted Polyester‐Based Nanocarriers

The development of delivery systems efficiently uptaken by cells is of due importance since sites of drug action are generally localized in subcellular compartments. Herein, naked and core–shell polymeric nanoparticles (NPs) have been produced from poly(lactic‐co‐glycolic acid)—PLGA, poly(ethylene oxide)‐b‐poly(ε‐caprolactone)—PEO‐b‐PCL, and poly(ethylene oxide)‐b‐poly(lactic acid)—PEO‐b‐PLA. The nanostructures are characterized and the cellular uptake behavior is evaluated. The data evidence that cellular uptake is enhanced as the length of the hydrophilic PEO‐stabilizing shell reduces and that high negative surface charge restricts cellular uptake. Furthermore, NPs of higher degree of hydrophobicity (PEO‐b‐PCL) are more efficiently internalized as compared to PEO‐b‐PLA NPs. Accordingly, taking into account our recent published results 1 and the findings of the current investigation, there should be a compromise regarding protein fouling and cellular uptake as resistance to nonspecific protein adsorption and enhanced cellular uptake are respectively directly and inversely related to the length of the PEO‐stabilizing shell.