Isolation of sinapic acid from broccoli using molecularly imprinted polymers

A molecularly imprinted polymer was synthesized for the purpose of sinapic acid isolation from Egyptian nutraceutical Botrytis italica, L. (broccoli) due to its prominent medicinal and wide pharmacological activities. A computational study was first developed to determine the optimal template to functional monomer molar ratio. Based on the computational results, five polymers were synthesized using a bulk polymerization method with sinapic acid as the template molecule. Evaluation of the synthesized polymers binding performance was carried out using batch rebinding assay, which revealed that the molecularly imprinted polymer of molar ratio (1:4:20), template to functional monomer (4‐vinyl pyridine) to crosslinker (ethylene glycol dimethacrylate) was of optimum performance, thus, this polymer was applied for sinapic acid isolation from closely related analogues. This represents a more practical approach to isolate sinapic acid from different natural extracts selectively.     

1-氨基乙内酰脲分子印迹聚合物的制备和吸附性能研究

以1-氨基乙内酰脲(AHD)为模板分子,α-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,采用本体聚合方法合成了分子印迹聚合物(M IP),考察了模板分子与功能单体不同比例下制备的M IP对模板分子的吸附性能。通过Scatchard分析,表明该印迹聚合物上存在一类等价的吸附位点,其结合位点的离解常数KD=4.33mmol/L。     

Synthesis and Evaluation of Molecularly Imprinted Polymers as Sorbents for Selective Extraction of Coumarins

Coumarin, 7-hydroxycoumarin and dicoumarol molecularly imprinted polymers (MIP) were synthesized by bulk polymerization. Methacrylic acid and 4-vinylpyridine were tested as functional monomers and methanol, ethanol, acetonitrile, toluene and chloroform were tested as porogens. The binding capabilities of the imprinted polymers were assessed by equilibrium binding analysis. Highest binding capacity was obtained for MIP prepared for the template 7-hydroxycoumarin synthesized in methacrylic acid as functional monomer, chloroform as porogen and methanol/water as analyte solvent. Scanning electron microscopy analysis documented its appropriate morphology. ATR-FTIR spectra confirmed successful polymerization of MIP. Coumarin structural analogues were employed to evaluate the polymer selectivity and it was found that polymer prepared for 7-hydroxycoumarin was selective for its template molecule. Kinetic studies showed relatively fast adsorption of analytes to MIPs (1 h). Rebinding properties of MIPs were evaluated by adsorption isotherms. The calculated data fitted well with experimental data showing that Freundlich isotherm is suitable for modelling the adsorption of tested coumarins on prepared MIPs. Applicability of polymer prepared for 7-hydroxycoumarin was tested for the selective extraction of coumarins from the sample of chicory.     

孔雀石绿分子印迹聚合物的制备及其吸附

采用本体聚合法制备了孔雀石绿分子印迹聚合物,对功能单体的种类及用量、交联剂用量、模板浓度和聚合时间等参数进行了优化,并通过等温吸附实验,考察聚合物的吸附性能。 结果表明,以α-甲基丙烯酸为功能单体,当孔雀石绿、α-甲基丙烯酸和乙二醇二甲基丙烯酸酯的摩尔比为1∶4∶20时,所合成的聚合物具有最大的吸附容量,印迹因子（α=QMIP/QNIP）可达到3.6,表明合成的印迹聚合物对孔雀石绿有良好的识别和富集能力。     

Computational Design and Fabrication of Enantioselective Recognition Sorbents for L-phenylalanine Benzyl Ester on Multiwalled Carbon Nanotubes Using Molecular Imprinting Technology

Computational strategies have been employed to investigate the influence of the nature of monomers and cross-linker in order to design three dimensional imprinted polymers with selective recognition sites for L-phenylalanine benzyl ester(L-PABE) molecule.Here, computational chemistry methods were applied to screen the molar quantity of functional monomers that interact with one mole of the template molecule. Effects of the nature of functional monomer, cross-linker, and molar ratio were determined computationally using density functional calculations with B3LYP functional and generic 6-31G basis set. Methacrylic acid(MAA) and ethylene glycol dimethacrylate(EGDMA) were used as the functional monomer and crosslinking agent, respectively. L-PABE imprinted polymer layered on multiwalled carbon nanotube(MWCNT) and conventional bulk MIP were synthesised and characterized as well. To investigate the influence of pre-organization of binding sites on the selectivity of L-PABE, respective non-imprinted polymers were also synthesised.MWCNT-MIPs and MIPs exhibited the highest adsorption capacity towards L-PABE. The synthesized polymers revealed characteristic adsorption features and selectivity towards L-PABE in comparison with those of its enantiomer analogues.     

苯甲酸分子印迹聚合物的制备及其吸附性能

以苯甲酸为模板分子,4-乙烯基吡啶为功能单体,乙二醇二甲基丙烯酸酯为交联剂,采用本体聚合法制备了高选择性识别的分子印迹聚合物。利用合成的聚合物作为吸附剂填充制备气体浓缩针装置,并用于挥发性有机化合物(VOCs)的气相色谱分析。实验结果表明:60℃下恒温聚合反应6h,模板分子、功能单体、交联剂的物质量比为1∶4∶20,预聚合时间为3h,溶剂为乙腈,模板分子为苯甲酸时,合成的分子印迹聚合物对苯系物的吸附量最大。     

丹酚酸A分子印迹聚合物制备及识别性能研究

以丹酚酸A为模板分子,丙烯酰胺(AM)、α-甲基丙烯酸(MAA)、2-乙烯基吡啶(2-VP)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,丙酮、乙酸乙酯、乙腈和甲醇为致孔剂,采用本体聚合法制备了一系列丹酚酸A分子印迹聚合物.通过静态平衡吸附实验和选择性实验考察了印迹聚合物的吸附性能...     

分子模拟-活性自由基聚合法制备山奈酚分子印迹整体柱及其性能评价

通过分子模拟研究模板分子与功能单体的相互作用,可以缩短优化时间,为选取合适的功能单体以及模板分子/功能单体比例提供依据.本研究以山奈酚为模板分子,通过分子模拟优化实验条件,确定以甲基丙烯酸(MAA)为最优的功能单体,山奈酚/MAA最佳比例为1∶4 (w/w).此外,以二苄基三硫代碳酸酯(DBTTC)为可逆加成-链断裂转移剂,乙二醇二甲基丙烯酸酯(EDMA)为交联剂,实现了仅需优化引发剂和可逆加成-断裂链转移聚合(RAFT)试剂即可制得性能优异的山奈酚分子印迹整体柱.此整体柱对山奈酚和相似物槲皮素的分离度为1.52,相对标准偏差为1.8%.实验结果表明,分子模拟计算简化了实验步骤,以DBTTC为RAFT试剂得到了具有更好形态和结构的分子印迹整体柱.     

冬凌草甲素分子印迹聚合物的制备及分子识别性能研究

以抗肿瘤药物分子冬凌草甲素为模板,甲基丙烯酸(MAA)为功能单体,乙二醇二甲基丙烯酸酯(ED-MA)作交联剂,采用沉淀聚合法和本体聚合法,制备对冬凌草甲素具有特定亲和选择性的分子印迹聚合物,并用激光粒度扫描和扫描电镜对聚合物的粒径和表面形貌进行了表征,采用平衡结合实验评价了两类分子印迹聚合物的吸附性能.结果表明,与使用...     

甲醛分子印迹聚合物的制备、性能及水产品测定

以甲醛为模板分子,α-甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,用氯仿做溶剂,制备了甲醛分子印迹聚合物,并优化了此制备方法,在模板分子、功能单体和交联剂的摩尔比为1:2:20,预聚合时间为4 h,聚合时间为8 h的条件下制备的聚合物对甲醛的特异性吸附能力最好,当甲醛溶液的浓度为2 mmol/L时聚合物对甲醛的吸附量达到了12.40×10^-2 mmol/g。 对市售鱿鱼处理后用高效液相色谱法测定得样品中甲醛的浓度是5.92 mg/Kg,将该样稀释100倍以后甲醛已无法检出,经MIP柱富集后检测计算样品中甲醛浓度为5.76 mg/Kg,表明该聚合物用于样品前处理高效且结果无显著性差异。     

Synthesis and binding site characteristics of 2,4,6-trichlorophenol-imprinted polymers

2,4,6-Trichlorophenol (2,4,6-TCP)-imprinted micro- and submicrospheres prepared by precipitation polymerization were compared with templated materials obtained by conventional bulk polymerization. The influence of the type and amount of functional monomer, the type and amount of cross-linker, polymerization temperature, porogen, and the ratio of template molecule and functional monomer to cross-linker on the size of the obtained particles were investigated. UV-Vis spectrophotometer experiments revealed that the microsphere polymers provided higher affinity to the template in contrast to imprinted polymers prepared by bulk polymerization. The binding properties of the microspheres, including binding isotherms and affinity distribution, were studied via Freundlich isotherm affinity distribution (FIAD) analysis. The obtained results indicated that microspheres prepared by precipitation polymerization provided superior rebinding properties during equilibrium binding in contrast to bulk polymers and submicrosphere polymers. Moreover, release experiments showed that 80% of rebound 2,4,6-TCP was released from the imprinted microspheres within the first 2 h, while more intimately bound 2,4,6-TCP molecules were released in the following 40 h. The morphologies and porosities of the resulting imprinted materials were characterized by scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis, respectively. The microsphere polymers exhibited a regular spherical shape with a high degree of monodispersity to the corresponding bulk polymers. Furthermore, the micro- and submicrospheres were characterized by narrow distribution of pores in contrast to a heterogeneity index of m = 0.6647 for the microsphere imprinted polymer.     

Voltammetric Determination of Valaciclovir Using a Molecularly Imprinted Polymer Modified Carbon Paste Electrode

A molecularly imprinted polymer (MIP) was rationally synthesized with the aid of computer based studies. The computational studies were used to screen for the most suitable template to functional monomer molar ratio. Two functional monomers were involved in the study (methacrylic acid and 4‐vinylpyridine). Four MIP ratios were synthesized in accordance with the results of the computational studies and their performance was evaluated using equilibrium rebinding assays. The MIP with the best performance was used as an additive in carbon paste electrodes for the voltammetric determination of valaciclovir (VCV). Following the optimization of voltammetric parameters, a linear response was obtained in the range of 1.0x10⁻⁶–7.0x10⁻⁴ M with a limit of detection at 4.45x10⁻⁷ M. The MIP modified carbon paste electrode was successfully applied for the determination of VCV in pure solutions and dosage form.     

Computational design and synthesis of molecular imprinted polymers with high selectivity for removal of aniline from contaminated water

A computational approach was developed to screening functional monomers and polymerization solvents for rational design of molecularly imprinted polymer (MIP). It was based on the comparison of the binding energy of the complexes between the template and different functional monomers. The effect of the polymerization solvent was included using the polarizable continuum model. According to the theoretical calculation results, the MIP with aniline as template was prepared by emulsion polymerization method using acrylamide (AAM) as functional monomer and divinylbenzene as cross-linker in carbon tetrachloride. The synthesized MIP was then tested by equilibrium-adsorption method, and the MIP demonstrated high removal efficiency to the aniline. The results of this study have indicated the possibility of using computer aided design for rational selection of functional monomers and solvents capable of removal of aniline from contaminated water.     

Surface imprinted polymers for oil denitrification with the combination of computational simulation and multi‐template molecular imprinting

Multi‐template molecular imprinting technique was employed for the theoretical study about industrial oil denitrification. Prior to the preparation of multi‐template molecularly imprinted polymers (MT‐MIPs), density functional theory was used for simulating the imprinted pre‐assembly systems composed of template (aniline, indole, or 3‐methylinndole) and monomer [methacrylic acid, acrylamide (AM), and 4‐vinylpyridine]. MT‐MIPs were synthesized as surface MIPs simply and successively by seeded emulsion polymerization or two‐stage precipitation polymerization. The experimental results were consistent with the simulative results, which demonstrated that AM was more suitable monomer together. In addition, seeded emulsion polymerization synthesized MT‐MIPs with better performance compared with two‐stage precipitation polymerization. The adsorption kinetics and adsorption isotherm of MT‐MIP prepared with AM using seeded emulsion polymerization were fitted with different models. The fitting results indicated that pseudo‐second‐order kinetics model and Freundlich isotherm model were suitable for describing the adsorption process of AM seeded emulsion polymerization. This study will provide a certain guidance and theoretical basis for introducing the combination of multi‐template molecular imprinting technique and computational simulation into the field of industrial denitrification. Copyright © 2015 John Wiley & Sons, Ltd.     

反乌头酸分子印迹聚合物微球的制备及其分子识别功能

以乙腈为分散剂,采用沉淀聚合法合成了反乌头酸分子印迹聚合物微球。研究了合成反应条件对聚合物形貌的影响,发现聚合前主客体氢键络合物和功能单体氢键低聚体是控制微球形成及其粒径大小的关键因素。通过振荡吸附法对聚合物的结合特性进行了评价,发现印迹聚合物微球对模板分子的识别选择性优于块状印迹聚合物和非印迹聚合物。     

苄嘧磺隆印迹聚合物的波谱分析及吸附性能研究

以苄嘧磺隆为模板分子, α-甲基丙烯酸为功能单体, 三甲氧基丙烷三甲基丙烯酸酯为交联剂, 二氯甲烷为致孔剂, 在20 ℃温度下, 采用紫外引发沉淀聚合方法制备了苄嘧磺隆分子印迹聚合物. 紫外光谱和核磁共振氢谱实验提示了聚合前模板分子与功能单体之间的相互作用主要是分子间氢键, 分子间氢键相互作用能和双氢键的键距由Hyperchem 7.0和Gaussian 03W软件分别计算为: －28.6163 kJ/mol和0.179～0.181 nm. 制备的印迹聚合物在高效液相色谱和吸附动力学实验中都表现出对模板分子有较强的吸附作用.     

The Syntheses and Characterization of Molecularly Imprinted Polymers for the Controlled Release of Bromhexine

Imprinted polymers are now being increasingly considered for active biomedical uses such as drug delivery. In this work, the use of molecularly imprinted polymers (MIPs) in designing new drug delivery devices was studied. Imprinted polymers were prepared from methacrylic acid (functional monomer), ethylene glycol dimethacrylate (cross-linker), and bromhexine (as a drug template) using bulk polymerization method. The influence of the template/functional monomer proportion and pH on the achievement of MIPs with pore cavities with a high enough affinity for the drug was investigated. The polymeric devices were further characterized by FT-IR, thermogravimetric analysis, scanning electron microscopy, and binding experiments. The imprinted polymers showed a higher affinity for bromhexine and a slower release rate than the non-imprinted polymers. The controlled release of bromhexine from the prepared imprinted polymers was investigated through in vitro dissolution tests by measuring absorbance at λ _max of 310 nm by HPLC-UV. The dissolution media employed were hydrochloric acid at the pH level of 3.0 and phosphate buffers, at pH levels of 6.0 and 8.0, maintained at 37.0 and 25.0 ± 0.5 °C. Results from the analyses showed the ability of MIP polymers to control the release of bromhexine In all cases The imprinted polymers showed a higher affinity for bromhexine and a slower release rate than the non-imprinted polymers. At the pH level of 3.0 and at the temperature of 25 °C, slower release of bromhexine imprinted polymer occurred.     

Monodispersed, molecularly imprinted polymers for cinchonidine by precipitation polymerization

Three monodispersed, molecularly imprinted polymers (MIPs) for cinchonidine (CD) have been synthesized by precipitation polymerization. MIP1 was prepared using methacrylic acid (MAA) as a functional monomer and divinylbenzene (DVB) as a cross-linker and MIP2 was prepared with further addition of 2-hydroxyethyl methacrylate (HEMA) as a co-monomer. For the preparation of MIP3, core-shell type MIP, monodispersed DVB homopolymers, which are prepared by precipitation polymerization, were used as a core and CD-imprinted MAA-DVB copolymer phases were coated onto the core. Three MIPs synthesized gave monodispersed, spherical beads in micrometer sizes. The binding characteristics and molecular recognition properties of MIP1-3 were examined by Scatchard analysis and chromatographic studies. The association constant of CD with MIP1 was the highest among MIPs prepared, while that with MIP3 was the lowest. The template molecule, CD, was more retained than its stereoisomer, cinchonine, on the three MIPs, and the stereoseparation factor of 38 was obtained with MIP3.     

Chiral separation of racemic mandelic acids by use of an ionic liquid-mediated imprinted monolith with a metal ion as self-assembly pivot

A new chiral stationary phase based on molecularly imprinted polymers (MIP) was prepared in ionic liquid by use of the metal pivot concept. Imprinted monoliths were synthesized by use of a mixture of R-mandelic acid (template), 4-vinylpyridine, ethylene glycol dimethacrylate, and several metal ions as pivot between the template and functional monomer. A ternary mixture of dimethyl sulfoxide–dimethylformamide–[BMIM]BF₄ containing metal ions was used as the porogenic system. Separation of the enantiomers of rac-mandelic acid was successfully achieved on the MIP thus obtained, with resolution of 1.87, whereas no enantiomer separation was observed on the imprinted monolithic column in the absence of metal ions. The effects of polymerization conditions, including the nature of the metal ion and the ratios of template to metal ions and template to functional monomer, on the chiral separation of mandelic acid were investigated. The results reveal that use of metal ions as a pivot, in combination with ionic liquid, is an effective method for preparation of a highly efficient MIP stationary phase for chiral separation.

Investigation of imprinting parameters and their recognition nature for quinine-molecularly imprinted polymers

A series of molecularly imprinted polymers (MIPs) was prepared using quinine as the template molecules by bulk polymerization. The presence of monomer-template solution complexes in non-covalent MIPs systems has been verified by both fluorescence and UV-vis spectrometric detection. The influence of different synthetic conditions (porogen, functional monomer, cross-linkers, initiation methods, monomer-template ratio, etc.) on recognition properties of the polymers was investigated. Scatchard analysis revealed that two classes of binding sites were formed in the imprinted polymer. The corresponding dissociation constants were estimated to be 45.00 micromol l(-1) and 1.42 mmol l(-1), respectively, by utilizing a multi-site recognition model. The binding characteristics of the imprinted polymers were explored in various solvents using equilibrium binding experiments. In the organic media, results suggested that polar interactions (hydrogen bonding, ionic interactions, etc.) between acidic monomer/polymer and template molecules were mainly responsible for the recognition, whereas in aqueous media, hydrophobic interactions had a remarkable non-specific contribution to the overall binding. The specificity of MIP was evaluated by rebinding the other structurally similar compounds. The results indicated that the imprinted polymers exhibited an excellent stereo-selectivity toward quinine.