Side chain functionality dominated the chromatography of N‐protected amino acid on molecularly imprinted polymer

Molecularly imprinted polymer (MIP) with N^α‐protected amino acid as the print molecule was prepared and used as the stationary phase for the chromatographic study of molecular recognition. Particles of MIP were prepared by photopolymerization of 4‐vinylpyridine in the presence of tert‐butyloxycarbonyl‐L ‐tyrosine (Boc‐L ‐Tyr) and packed into a column for the chromatographic resolution of Boc‐L ‐Tyr and tert‐butyloxycarbonyl‐L ‐phenylalanine (Boc‐L ‐Phe). These two N^α‐protected amino acids that differ from each other in the side chain with one hydroxyl group on the benzene ring could be well separated on the MIP. A separation factor of about two was achieved by using a mixture of acetonitrile (99.5 v/v %) and acetic acid (0.5 v/v %) as the mobile phase. Results suggest that the interaction between hydroxyl group in the side chain of amino acid and pyridine in the polymer dominated the selective adsorption of print molecule on the MIP. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Preparation and characterization of uniform molecularly imprinted polymer beads for separation of triazine herbicides

Uniform molecularly imprinted polymer beads were synthesized by precipitation polymerization for separation of triazine herbicides. A series of imprinted polymers were prepared using ametryn as template and divinylbenzene as crosslinking monomer, in combination with three different functional monomers under different solvent conditions. Under optimized reaction conditions, we obtained uniform molecularly imprinted polymer microspheres that display favorable molecular binding selectivity for triazine herbicides. The imprinted polymer beads synthesized using methacrylic acid as functional monomer in a mixture of methyl ethyl ketone and heptane showed the best results in terms of particle size distribution and molecular selectivity. Compared with nonimprinted polymer microspheres, the imprinted microspheres displayed significantly higher binding for a group of triazine herbicides including atrazine, simazine, propazine, ametryn, prometryn, and terbutryn. For the first time, precipitation polymerization has been used to produce highly uniform imprinted microspheres suitable for affinity separation of triazine herbicides. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

杨梅黄素分子印迹聚合物的制备及其识别性能研究

以杨梅黄素(MYR)为模板分子、2-乙烯基吡啶(2-VP)为功能单体、二甲基乙二醇丙烯酸酯(EDMA)为交联剂,偶氮二异丁腈(AIBN)为引发剂,甲醇为致孔剂,采用分子印迹技术制备了杨梅黄素分子印迹聚合物(MYR-MIP)。通过红外光谱、扫描电镜、热重分析等技术表征了MYR-MIP的理化性能;采用紫外光谱分析研究了MYR-MIP对MYR的等温吸附和动力学吸附特性,研究结果表明MYR-MIP对MYR具有良好的特异性吸附,并且在2 h内达到平衡吸附;高效液相色谱分析表明MYR-MIP对MYR具有优良的选择识别特性。     

Studies on the preparation and properties of inorganic molecularly imprinted polymer (MIP) based on tetraethoxysilane and silane coupling agents

Inorganic molecularly imprinted polymer (MIP) based on tetraethoxysilane (TEOS), methyl triethoxysilane (MTEOS), and phenyl triethoxysilane (PTEOS) by sol‐gel process has been developed. The MIP's preparation conditions, H₂O/Si molar ratios (R), template removal procedures, calcination temperatures, and quantity of ammonium hydroxide were investigated. The competition experiments of the MIP for template (caffeine, CAF) and analogue (theophylline, TH) were analyzed by high‐performance liquid chromatography (HPLC). The results showed that the Ad_CAF decreased with an increase of the H₂O/Si molar ratios, but the selectivity (α) increased with an increase of the H₂O/Si molar ratios in the MIP. In addition, in a comparison of the procedures for removing the template, calcination obtained better efficiency and higher selectivity than extraction. The optimum adsorption and selectivity of MIP were obtained with R = 10 and the template was removed by calcination at 600°C. Moreover, the selectivity of the MIP (283.9) was greater than the nonimprinted polymer (2.45) under optimum preparation conditions. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Binding and recognition ability of molecularly imprinted polymer toward p-nitrophenol

p-Nitrophenol is a hazardous phenolic compound and its separation and determination is very necessary to protect public health and environmental quality. In this article, macromolecule polyethyleneimine (PEI) grafted on the surface of silica particles was crosslinked using p-nitrophenol as a template and diepoxyalkyl (669) as a crosslinking agent, and molecularly imprinted polymer on the surfaces of silica gel MIP-PEI/SiO₂ was prepared. The binding and recognition ability of MIP-PEI/SiO₂ for p-nitrophenol were researched using batch and dynamic methods. The experimental results showed that MIP-PEI/SiO₂ had high affinity, specific recognition ability, and excellent selectivity for p-nitrophenol. The saturated binding amount could reach to 155.5 mg g⁻¹. The selectivity coefficients relative to m-nitrophenol and chlorophenol were 45.80 and 117.5, respectively. The empirical Freundlich isotherm was found to describe well the equilibrium binding data. pH of sample solution was found to have a strong influence on the binding amount. MIP-PEI/SiO₂ was regenerated easily using diluted hydrochloric acid solution as eluent and MIP-PEI/SiO₂ possesses better reusability. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

分子印迹聚合物结合点的选择性修饰

以槲皮素为模板分子,甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,制备了分子印迹聚合物(MIP),并以重氮甲烷为修饰剂,对MIP的结合点进行了选择性修饰,探讨了模板分子浓度、溶剂及重氮甲烷用量等对修饰效果的影响。结果表明,选择性修饰能明显提高MIP的识别能力与吸附速度,以柚皮素为竞争分子,分离因子可从修饰前的1.60提高到修饰后的3.06,吸附平衡时间从修饰前的100 min降低至修饰后的60 min;在一定范围内提高模板分子浓度,增大重氮甲烷用量,采用形成氢键能力较弱的溶剂,均能提高修饰效果。测定了修饰前后MIP中不同结合点吸附过程的焓变、熵变和自由能变化,从热力学角度对修饰效果和修饰机理作了进一步的分析。     

Surface plasmon resonance studies on molecularly imprinted films

Novel molecular recognition films were prepared from modified polysulfone having perillaldehyde moiety as a side group. The molecular recognition films were obtained from perillaldehyde polysulfone by adopting 9‐ethyladenine as a print molecule. The molecular recognition phenomena were studied by surface plasmon resonance (SPR) spectroscopy. Adsorption of adenosine (As) and guanosine (Gs) in the molecularly imprinted film was studied. Dual adsorption isotherms were observed for As in 9‐EA imprinted films, while nonspecific adsorption isotherms for Gs in those films. This revealed that the molecular recognition sites toward As were constructed in the films thus prepared. The apparent affinity constant toward As determined by using apparent adsorption isotherms ranged from 7.90 × 10³ to 3.31 × 10⁴ mol^?1 dm³. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation and evaluation of a molecularly imprinted polymer for tolazoline

A uniformly sized molecularly imprinted polymer for the peripheral vasodilator drug tolazoline (T‐MIP) was prepared, and a nonimprinted polymer (NIP) was also synthesized in the same way but in the absence of the template. The T‐MIP was prepared with methylacrylic acid as functional monomer and ethylene glycol dimethacrylate as crosslinker by a multistep swelling and polymerization method. These imprinted materials were characterized by scanning electron microscopy, nitrogen adsorption, and static adsorption experiments. Binding studies were also performed to evaluate the uptake of T‐MIP and NIP with the results that T‐MIP had a significantly higher binding capacity for tolazoline (T) than did NIP. The maximum static adsorption capacities of T‐MIP and NIP for T were 78.9 and 38.8 μmol/g, respectively. The T‐MIPs and NIPs were used as stationary phases of solid‐phase extraction (SPE), and a relative selectivity coefficient (k′) value of 5.21 was obtained, which showed that the T‐MIP sorbent had higher selectivity than the NIP sorbent. The method was applied to the determination of T in urine samples. The prepared polymer sorbent showed promise for SPE for gas chromatography determination of T in urine samples. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation and characteristics of a dummy molecularly imprinted polymer for phenol

A dummy molecularly imprinted polymers (DMIP) for phenol was synthesized by a thermal polymerization method with acrylamide as the functional monomer, ethylene dimethacrylate as the crosslinker, 2,2‐azobisisobutyronitrile as the free‐radical initiator, acetonitrile as the porogenic solvent, and sulfadiazine, a phenol analogue, as the template. In comparison to other adsorbents, the synthesized DMIP showed a higher capacity and rate of adsorption. The adsorption amount of the DMIP adsorbents for phenol reached 6.09 ± 0.15 mg/g, and the adsorption rate of the DMIP was about 0.406 ± 0.01 mg g^?1·min^?1. The results indicate that the Freundlich model fit the adsorption model of DMIP for phenol. The adsorption model of DMIP for phenol was multilayer adsorption. This showed that the DMIP synthesized by bulk polymerization could be used as a novel adsorbent for the removal of phenol from contaminated water. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

三硝基甲苯分子印迹电化学传感器的制备和应用

以三硝基甲苯（TNT）为模板分子,甲基丙烯酸（MAA）为功能单体,采用乳液聚合法制备TNT的分子印迹聚合物（MIPs）。将制备的MIPs分散在溶剂中,通过表面涂覆法制备出检测TNT的分子印迹电化学传感器。紫外光谱表明TNT与MAA之间存在相互作用力,有助于形成结构稳定、亲和性强的MIPs。利用扫描电镜观测不同制备条件下印迹聚合物的表观形貌,发现溶剂用量为30mL、乳化剂用量为12mg时制备的聚合物形貌较优异。吸附实验表明MIPs对TNT的吸附量随着TNT初始浓度的增加而增加,140min后达到最大吸附量的95%。MIPs对TNT的分离常数远大于RDX和DNT,对RDX和DNT的选择性系数均达到4.4以上,说明MIPs对TNT有较好的选择性吸附能力。铁氰化钾探针实验和对TNT的响应曲线验证了电化学传感器的成功制备,该传感器富集3min就达到了最大电流值的94%,5min内达到吸附平衡。TNT浓度在0.1~5mg/mL的范围内与峰电流有良好的线性关系,检出限为0.06mg/mL。MIPs传感器对TNT的电流响应分别为DNT和RDX的3.13倍、3.27倍,说明其对TNT分子具有很强的特异性识别能力。     

温敏型分子印迹水凝胶的研究进展

近年来分子印迹技术发展迅速,以其高选择性、预定识别性等优点,在分离工程、化学传感器及模拟酶催化等领域均得到了广泛应用,但是其在水凝胶方面的研究却较少。将温敏水凝胶引入分子印迹技术制备温敏印迹水凝胶不仅能保持其特异识别性能,还赋予其对环境温度变化的响应性,使其对模板分子的识别具有温度可控性。本文简单介绍了温敏型分子印迹水凝胶的基本原理和制备方法,基于模板分子种类的不同,着重综述了温敏印迹凝胶在金属离子、有机小分子及生物蛋白方面的应用。同时对温敏印迹水凝胶的发展方向进行了展望,指出温敏印迹水凝胶将在物料分离、药物控释等领域表现出较好的应用前景。     

Preparation and utilization of microporous molecularly imprinted polymer for sustained release of tetracycline

A polyacrylate tetracycline (TC) selective microporous molecularly imprinted polymer was prepared in three different porogenic solvents (chloroform, acetonitrile, and methanol) via precipitation polymerization, using methacrylic acid monomer, ethylene glycol dimethacrylate crosslinker, and TC as template. In all three solvents this method produced microporous particles in the scale range (200–400 nm), simply, quickly, cleanly, and in good yield. The effect of polarity of porogenic solvents on binding capacity was investigated. The imprinted polymer prepared in chloroform gave much higher binding capacity (K_D = 198.6) for TC than the polymers prepared in acetonitrile (K_D = 133.2) or methanol (K_D = 104.7). The selectivity of imprinted polymers was evaluated by rebinding other structurally similar compounds. The results clearly indicated that the imprinted acrylate polymer exhibits an excellent selectivity toward TC, and has better ability to control the release of TC than the non‐imprinted polymer.© 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

石杉碱甲分子印迹聚合物的制备及缓释特性

石杉碱甲(Hup A)是从蛇足石杉中提取出来的可逆性乙酰胆碱酯酶抑制剂，对AD症具有良好的治疗效果。用分子印迹和沉淀聚合技术，以甲基丙烯酸为功能单体，乙二醇二甲基丙烯酸乙酯为交联剂成功制备石杉碱甲分子印迹聚合物（MIP）。通过傅里叶变换红外光谱，热重分析，扫描电子显微镜对印迹聚合物（MIP）进行了表征。通过静态吸附、动态吸附、体外释药和MTT等实验对MIP性能进行了评价。实验结果表明MIP对石杉碱甲存在特异性和非特异性两种结合位点。市售石杉碱甲片在1h内快速释放，累积释放率达90%以上，有明显的突释现象。而MIP在1h后释放平缓，在24h附近达到平衡，可以达到缓慢释放的效果。释放动力学符合Peppas模型，释放指数n=0.48，为非Fickian扩散机理。MIP生物相容性良好，L929小鼠成纤维细胞对MIP的细胞毒性数据显示，细胞存活率高于93%。     

Solid-phase extraction of S-(-)-amlodipine from plasma with a uniformly sized molecularly imprinted polymer

To specifically extract S-(-)-amlodipine from plasma, uniformly sized molecularly imprinted polymers (MIPs) for S-(-)-amlodipine were prepared in an aqueous system by multistep swelling and polymerization with methacrylic acid as a functional monomer, ethylene glycol dimethacrylate as a crosslinker, and toluene as a porogen. Scanning electron microscopy was used to identify the structural features of the obtained polymers. ¹H-NMR and high-performance liquid chromatographic analysis were performed to explore the possible recognition mechanism. The results reveal that spherical polymer beads with uniform size and good monodispersity were obtained, and the MIPs showed specific recognition ability for the template molecule. The ionic hydrophobic and hydrogen-bonding interactions were inferred to play an important role in the recognition mechanism. The results indicate that the MIPs could be used as a solid-phase extraction sorbent for the concentration and purification of S-(-)-amlodipine from plasma with a high efficiency. The linear range was 0.25–8.00 μg/mL with a correlation coefficient of 0.9948. The average recovery was 98.3% with relative standard deviation (RSD) less than 9.1%. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis of novel photoresponsive molecularly imprinted polymer microspheres with special binding properties

An azobenzene‐containing molecularly imprinting polymer microsphere with photoresponsive binding properties toward 2,4‐dichlorophenoxyacetic acid (2,4‐D) was successful prepared via silica surface polymerization. The number‐average diameters of silica and imprinting polymer microsphere are 0.5 and 0.7 μm, respectively. The static adsorption, binding and selectivity experiments were performed to investigate the adsorption properties and recognition characteristics of the polymers for 2,4‐D. The equilibrium adsorptive experiments indicated that 2,4‐D‐SMIP(surface molecularly imprinted polymers) has significantly higher adsorption capacity for 2,4‐D than its nonimprinted polymers (SNIP).The binding constant K_d and apparent maximum number Q_max of the imprinted polymer were determined by Scatchard analysis as 0.054 mmol L^?1 and 0.167 mmol g^?1_, respectively. The result of photoregulated release and uptake of 2,4‐D experiment demonstrated that azo‐containing SMIP can make use of light and change it into mechanical properties to release and take up the template molecules. It means that the SMIP can be controlled by light. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 869‐876, 2013     

辛弗林分子印迹聚合物的制备及吸附性能评价

利用分子印迹技术,以辛弗林(SYN)为模板分子,甲基丙烯酸(MAA)为功能单体,二甲基乙二醇丙烯酸酯(EDMA)为交联剂,偶氮二异丁腈(AIBN)为引发剂,在四氢呋喃(THF)溶液中制备了辛弗林分子印迹聚合物(SYN-MIP);通过紫外光谱法研究了SYN与MAA的非共价作用,并通过静态平衡实验评价了SYN-MIP的吸附...     

分子印迹技术制备与应用进展

综述了分子印迹技术的制备方法及在色谱分离、固相萃取、膜分离、免疫分析、仿生传感、酶催化模拟等领域的应用。并指出对于分子印迹和识别的机理、在水相中实现分子印迹识别和大分子印迹聚合物的合成等方面需进一步研究。     

水相中马尿酸分子印迹聚合物的制备及其性能研究

采用分子印迹技术,以马尿酸为模板分子,在水相中制备其印迹聚合物。用于液相色谱固定相,结果表明,该聚合物固定相表现出良好的分离选择性,能够使马尿酸与和其结构相似的苯甲酸及咖啡酸快速基线分离。并通过平衡吸附法分析了印迹聚合物的识别特性,结果表明分子印迹聚合物对马尿酸有特异性吸附。     

Using molecularly imprinted polymer for protecting functional group in organic reaction

In this study, a novel method of selective protecting group based on molecularly imprinted polymer for regioselective organic reaction is reported. The simplicity, convenience and feasibility of this method may be illustrated by the protection of hydroxyl group at C17 or C3 of β‐estradiol in the reaction between β‐estradiol and diphenylphosphinic chloride. Polymers to protect hydroxyl group at C17 or at C3, both demonstrated excellent protection effect. In polymers imprinted with 2‐methyl‐cyclopentanol template to protect hydroxyl group at C17, the proportion of 3‐phosphate was almost as high as 100%. In molecularly imprinted polymer synthesized using 5,6,7,8‐Tetrahydro‐2‐naphthol as a template to protect hydroxyl group at C3, the proportion of 17‐phosphate reached 98.2%. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation of molecularly imprinted polymers in supercritical carbon dioxide

Molecularly imprinted polymer nanoparticles were prepared in supercritical carbon dioxide using a noncovalent imprinting approach. In the present work, propranolol was used as a model template, methacrylic acid as a functional monomer, and divinylbenzene as a crosslinker. Under a high dilution condition, the heterogeneous polymerization resulted in discrete crosslinked polymer nanoparticles. Compared with the nonimprinted polymers, the imprinted nanoparticles displayed much higher propranolol uptake in a low polarity organic solvent. The use of a single enantiomer (S)‐propranolol as the template clearly demonstrated that the imprinted binding sites are chiral‐selective, with a cross‐reactivity towards (R)‐propranolol of less than 5%. The overall binding performance of the imprinted nanoparticles was comparable to imprinted polymers prepared in conventional organic solvents. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2863–2867, 2006