分子印迹手性分离过程的热力学研究

以丙烯酰胺为功能单体, 以二甲基丙烯酸乙二醇酯为交联剂, 在模板分子N-叔丁氧羰酰-L-色氨酸(N-Boc-L-Trp)和N-叔丁氧羰酰-L-酪氨酸(N-Boc-L-Tyr)的存在下, 分别采用光引发聚合和热引发聚合制备了N-Boc-L-Trp和N-Boc-L-Tyr的分子印迹聚合物(MIPs), 进行分子印迹手性分离过程的热力学研究. 测定了分离过程的熵变、焓变和自由能变化. 结果显示, 在流动相中添加异丙醇或甲醇等强氢键竞争性溶剂时, 熵变对分离起到了主要作用, 而且分离过程中的溶剂化对分离的影响也非常大. 分子印迹聚合物对印迹分子和非印迹分子进行分子识别的主要作用是印迹聚合物与印迹分子匹配的三维空间结构.     

N-叔丁氧羰酰-L-色氨酸分子印迹整体柱的制备及性能研究

采用溶胶-凝胶法,以N-叔丁氧羰酰-L色氨酸为模板分子,3-氨丙基三乙氧基硅烷为功能单体,四乙氧基硅烷为交联剂,制备了分子印迹整体柱.对制备过程影响较大的因素温度、酸度等条件进行了优化.用氮气吸附法对聚合物孔径分布进行了表征,聚合物上含有模板分子形成的介孔,平均孔径63左右.将印迹柱用于N-叔丁氧羰酰-DL-色氨酸分析...     

(2-甲基丙烯酰胺)乙氧基-2-甲基丙烯酸乙二醇单酯基质分子印迹手性分离介质的合成与表征

通过甲基丙烯酰氯和二甘醇胺反应设计合成了一种交联剂(2-甲基丙烯酰胺)乙氧基-2-甲基丙烯酸乙二醇单酯,以自行合成的(2-甲基丙烯酰胺)乙氧基-2-甲基丙烯酸乙二醇单酯为交联剂,丙烯酰胺为功能单体,合成了一种用于手性分离的N-叔丁氧羰酰-L-色氨酸(N-Boc-L-Trp,N-[(tert-butoxy)carbonyl]-tryptophan)的分子印迹聚合物。评价了该分子印迹聚合物作为高效液相色谱柱填料对N-叔丁氧羰酰-色氨酸(N-Boc-Trp)的手性拆分能力。结果表明:当检测波长为280 nm,流动相为V(甲醇)∶V(水)=80∶20,流速0.8 mL/min时,该填料实现了对N-Boc-Trp外消旋混合物的手性拆分,显示出良好的选择识别性能。     

2,4-二氯苯氧乙酸分子印迹整体柱的制备、表征及色谱性能研究

以2,4-二氯苯氧乙酸分子为模板,甲基丙烯酸为单体,乙二醇二甲基丙烯酸酯为交联剂,甲苯和十二醇为混合致孔剂,采用热引发原位聚合法制备了作为高效液相色谱固定相的分子印迹整体柱.用红外光谱、扫描电镜、比表面积分析法对聚合物进行了表征.考察了模板分子在不同条件下合成的印迹整体柱及空白整体柱上容量因子的变化规律,同时探讨了流动相中甲醇的体积分数、pH值、流速对印迹整体柱分离性能的影响.结果表明,在优化的合成条件下制备的分子印迹整体柱可在15 min内分离2,4-二氯苯氧乙酸及其类似物苯氧乙酸,分离度为1.52.对柑桔提取液进行了分离测试,结果满意.     

分子印迹固相萃取/高效液相色谱法检测黄瓜中灭蝇胺

以灭蝇胺为模板分子,甲基丙烯酸(MAA)为功能单体,乙二醇二甲基丙烯酸酯(EDMA)为交联剂,甲苯和异辛烷为二元致孔剂,采用低温光引发、本体聚合法制备了灭蝇胺的分子印迹聚合物.通过平衡吸附实验、扫描电镜、红外光谱以及压汞仪等多种手段对制备的印迹和非印迹聚合物进行了测定与表征,结果表明所制备的印迹聚合物对模板分子具有明显的特异性吸附作用.Scatchard分析证明灭蝇胺分子印迹聚合物对灭蝇胺分子的吸附存在两类不同结合位点,最大表观结合量(Qmax)和平衡解离常数(Kd)分别为Qmax1=1.19μmol/g,Kd1=1.31 μmol/L;Qmax2 =2.46 μmol/g,Kd2=4.84 μmol/L.用该聚合物制备的灭蝇胺分子印迹固相萃取柱处理样品,结合高效液相色谱法可快速有效地检测黄瓜样品中的灭蝇胺,线性范围为0.1～10 mg/L(r =0.9991),检出限(S/N=3)为0.05 mg/L.该方法快速简便,效果优于商品化的固相萃取柱.     

紫外光聚合法制备L-DBTA手性分子印迹聚合物的研究Ⅰ.紫外光聚合制备条件

以丙烯酸为功能单体,二苯甲酰-L-酒石酸(L-DBTA)为模板分子,三羟甲基丙烷三丙烯酸酯(TMPTA)为交联剂,采用光聚合方法合成了L-DBTA手性分子印迹聚合物,讨论了功能单体种类、功能单体用量、交联剂用量、引发剂用量、三乙胺用量、光聚合温度、光聚合时间、光强度等对L-DBTA手性分子印迹聚合物合成的影响。通过L-DBTA手性分子印迹聚合物对底物的结合实验分析,表明手性分子印迹聚合物对L-DBTA具有很好的识别性,L-DBTA的选择性比二苯甲酰-D-酒石酸(D-DBTA)高,其分离因子可达5．41。     

新型引发转移终止剂引发烯类单体活性自由基聚合及共聚合

引发转移终止剂 (Iniferter)是最早实现活性自由基聚合的方法 ,尽管它对聚合过程控制得不是很好 ,但是可聚合单体多 ,能方便地制备接枝和嵌段共聚物 .因此 ,近 2 0年来 ,它一直是高分子合成化学领域的一个研究热点 ,许多新颖结构的引发转移终止剂被合成并用于制备端基功能化聚合物、遥爪聚合物、大分子单体以及接枝和嵌段聚合物等 .本文扼要综述了引发转移终止剂的发展 ,着重综述了我们研究组在C—C键型高活性热引发转移终止剂、新的光引发转移终止剂、可聚合光引发转移终止剂、新型多功能引发转移终止剂和大分子光引发转移终止剂 5个方面的研究进展     

合成引发方式对槲皮素-钴(Ⅱ)配位印迹聚合物结构与性能的影响

以槲皮素-钴(Ⅱ)的配合物为模板分子,在强极性甲醇溶剂中分别采用低温光引发和高温热引发聚合制备槲皮素-钴(Ⅱ)配位印迹聚合物.紫外-可见光谱分析确定了槲皮素与钴(Ⅱ)形成配合物的最佳配位比.根据印迹聚合物的平衡结合量优化功能单体丙烯酰胺用量.利用红外光谱、透射电镜和平衡结合实验,考察不同引发方式对聚合物的结构、微观形貌及结合性能的影响.进一步通过特异吸附容量和印迹指数确定,低温光引发聚合更适于配位分子印迹聚合物的制备.同时研究了不同阳、阴离子对印迹聚合物选择识别性的影响.结果表明光引发的金属配位分子印迹聚合物具有良好的吸附选择性,印迹指数可达3.919.     

咪草烟分子印迹聚合物的制备及其选择性吸附性能的研究

以丙烯酸为聚合单体,TMPTA为交联剂,AIBN为引发剂,咪草烟为模板分子,采用在低温光聚合的方法,制备了对咪草烟分子具有选择性识别能力的分子印迹聚合物．通过IR和HPLC表征,咪草烟分子印迹聚合物对咪草烟分子具有良好的识别作用．     

一个制备叔丁氧羰酰氨基酸衍生物的简单方法

近年来,叔丁氧羰酰基在多肽合成中已被广泛地用来保护氨基酸的氨基。它的主要优点是对酸具有较高的敏感性,可以用氯化氢的醇溶液或三氟乙酸酸解而去除。对碱稳定且不被催化氢解和肼解。叔丁氧羰酰氨基酸衍生物的制备方法,最初是用α-异(?)酸酯与叔丁醇反应而获得,后来大多是采用各种活化的叔丁氧羰酰基衍生物作为叔丁氧羰酰化的试剂。目前最常用的试剂是1959年 R.Schwyzer     

Comparison of three cross‐linking agents for imprinting diethylstilbestrol in solid‐phase extraction

Molecularly imprinted polymer (MIP) has been heavily studied for years. However, most efforts focused on functional monomer and particular study of cross‐linking agents on imprinting effect and pore structure is rare. In this paper, diethylstilbestrol (DES) imprinted polymers cross‐linked by three types of agents and their imprinting effects in solid‐phase extraction (SPE) were discussed. Evolution of UV spectral and simulation of cross‐linking agents or monomer mixed with DES revealed that there was a particular interaction between divinylbenzene and DES. Clear imprinting effects towards DES showed for divinylbenzene made imprinted polymer (DM), with imprinting factors up to 16.02 (STD = 2.20), while the other two imprinted polymers showed limited effects with imprinting factors of 4.95 (STD = 0.45) and 1.63 (STD = 0.54). Specific surface areas, pore volumes, and pore size distributions of the particles also confirmed that DM showed distinguished structure, and the average pore size of it was just fit the size of DES and bisphenol A (BPA), while no pore was found in divinylbenzene made blank polymer. Other imprinted and non‐imprinted polymers showed no pore or big pores relatively. These results show that the cross‐linking monomer is not merely an inert component for the MIPs, it could play a positive role in promoting interactions with the template to afford molecular recognition in imprinting DES. Copyright © 2011 John Wiley & Sons, Ltd.     

Preparation and Evaluation of Melamine Molecularly Imprinted Polymers by Thermal‐ and Photo‐initiation Methods

Melamine imprinted polymers (MIPs) have been prepared using identical polymer formulation by both thermal‐ and photo‐initiation method, respectively. Physical characterization of the polymers revealed that the different polymerization methods led to the slight differences in both polymer structures and performance by scanning electron microscope (SEM), infrared absorption (IR), and mercury analyzer (MA). Both MIPs were used as selective sorbents for the solid phase extraction (SPE) of melamine in milk powders, followed by the determination coupled to HPLC. The recoveries of melamine in spiked milk powders were obtained in the range of 92.4‐97.7% and 94.6‐99.7%, for both MIP_thermal and MIP_photo, respectively.     

RECENT ADVANCES IN THE PREPARATION OF MOLECULARLY IMPRINTED POLYMERS VIA CONTROLLED RADICAL POLYMERIZATION TECHNIQUES

Molecular imprinting technique is a simple and efficient method for the preparation of polymer materials （i. e., molecularly imprinted polymers, MIPs） with tailor-made recognition sites for certain target molecules. The resulting MIPs have proven to be versatile synthetic receptors due to their high specific recognition ability, favorable mechanical, thermal and chemical stability, and ease of preparation. Recent years have witnessed significant progress in the synthesis and applications of MIPs. This review focus on the recent developments and advances in the preparation of MIPs via various controlled radical polymerization techniques.     

非那西汀印迹聚合物固相萃取性能研究

研究非那西汀分子印迹聚合物的固相萃取性能。用本体聚合法制备非那西汀分子印迹聚合物,通过静态平衡吸附试验及固相萃取试验,研究其固相萃取性能。非那西汀模板聚合物的吸附能力明显强于空白聚合物。模板聚合物对浓度为0.03mmol/L的非那西汀标准溶液一次性萃取率为74.2%。非那西汀印迹聚合物对非那西汀具有特异性识别性能,可作为固相萃取固定相的应用研究。     

蛋白质分子印迹聚合物研究

分子识别现象在生命过程中扮演着极其重要的角色,对此进行研究和探索是化学和生物学领域的核心课题,制备具有分子识别能力的人工受体是对该领域科学工作者的一个持久挑战．为此,相关研究人员进行了多方努力,创造性地发展了许多崭新的方法和手段,其中的分子印迹聚合物制备技术就是这些方法和手段中的一种.     

石杉碱甲分子印迹聚合物的制备、表征及其吸附性能

以硅胶为牺牲载体,石杉碱甲为模板分子,甲基丙烯酸为功能单体,二乙烯基苯为交联剂,偶氮二异丁腈为引发剂,首次制备了石杉碱甲分子印迹聚合物,并用红外光谱、扫描电子显微镜和热重分析研究了印迹聚合物的结构特征,用静态吸附法和Scatchard分析法研究了印迹聚合物的识别效能和表面位点分布特征。 结果表明,石杉碱甲印迹聚合物对模板分子具有较好的选择吸附性能,选择系数为1.399。Scatchard分析表明,印迹聚合物基体中主要存有两类吸附位点,对高亲和位点：平衡离解常数Kd1=0.776 g/L,最大表观结合量Qmax1=0.213 mg/g;对低亲和位点：平衡离解常数Kd2=0.169 g/L,最大表观结合量Qmax2=0.832 mg/g。 当该聚合物用于微固相萃取蛇足石杉粗提液中的石杉碱甲时,石杉碱甲回收率为93.5%,显示了较好的富集效果。     

Chiral separation by （S）-naproxen imprinted monolithic column with mixed functional monomers

Molecularly imprinted polymers (MIPs), using (S)-naproxen as template and the combination of butyl methacrylate (BMA) and MAA (1:1 molar ratio) as functional monomers were synthesized by an in situ polymerization reaction. The rendered monolithic column was evaluated in HPLC mode. The result showed that the monolithic MIPs with the combination of two monomers produced better chiral resolution of rac-naproxen (Rs=1.55) and column efficiencies of imprinted molecules (N=2860 plates/m)than that with pure MAA.     

Selective separation of lambdacyhalothrin by porous/magnetic molecularly imprinted polymers prepared by Pickering emulsion polymerization

Porous/magnetic molecularly imprinted polymers (PM‐MIPs) were prepared by Pickering emulsion polymerization. The reaction was carried out in an oil/water emulsion using magnetic halloysite nanotubes as the stabilizer instead of a toxic surfactant. In the oil phase, the imprinting process was conducted by radical polymerization of functional and cross‐linked monomers, and porogen chloroform generated steam under the high reaction temperature, which resulted in some pores decorated with easily accessible molecular binding sites within the as‐made PM‐MIPs. The characterization demonstrated that the PM‐MIPs were porous and magnetic inorganic–polymer composite microparticles with magnetic sensitivity (M_s = 0.7448 emu/g), thermal stability (below 473 K) and magnetic stability (over the pH range of 2.0–8.0). The PM‐MIPs were used as a sorbent for the selective binding of lambdacyhalothrin (LC) and rapidly separated under an external magnetic field. The Freundlich isotherm model gave a good fit to the experimental data. The adsorption kinetics of the PM‐MIPs was well described by pseudo‐second‐order kinetics, indicating that the chemical process could be the rate‐limiting step in the adsorption of LC. The selective recognition experiments exhibited the outstanding selective adsorption effect of the PM‐MIPs for target LC. Moreover, the PM‐MIPs regeneration without significant loss in adsorption capacity was demonstrated by at least four repeated cycles.     

Photo‐stimulated “turn‐on/off” molecularly imprinted polymers based on magnetic mesoporous silicon surface for efficient detection of sulfamerazine

In this study, novel photo‐stimulated molecularly imprinted polymers based on magnetic mesoporous carrier surface were developed for selective identification and intelligent separation of sulfamerazine in complex samples. The photosensitive monomer of the molecularly imprinted polymers was azobenzene derivative 5‐[(4‐(methacryloyloxy)phenyl) diazenyl] isophthalic acid with stimulus reaction mechanisms, which has photoisomerization between trans and cis for N=N bonds. Further, the properties of the photo‐stimulated molecularly imprinted polymers were further evaluated through several sets of adsorption experiments. It illustrated that the maximum adsorption amount is 0.45 mmol/L. By ultraviolet spectrophotometry, the material reaches typical characteristic peaks of photo sensitivity, and the cycle time is 16 min. Three adsorption and desorption processes were repeated, the adsorption rate reached 34.4%. Overall, the photo‐stimulated molecularly imprinted polymers can enrich and separate determine sulfamerazine with high selectivity, which have good recovery for real samples.