大黄酸磁性印迹聚合物的制备及其应用研究

以SiO2包覆的磁性粒子为载体,大黄酸为模板分子,苯基和氨基硅烷偶联剂为二元功能单体,正硅酸乙酯为交联剂制备大黄酸磁性印迹聚合物。采用红外光谱和扫描电镜对该印迹聚合物进行表征。结果表明,该印迹聚合物颗粒分散均匀,呈立方体结构,印迹壳层厚度约75～100nm。结合磁固相萃取技术和高效液相色谱技术对大黄蒽醌类组分进行富集分离,实现猕猴桃根提取液中大黄酸、大黄素、大黄酚和大黄素甲醚等组分的同时分离、富集和检测。     

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．     

Fabrication of the Monolithic Fiber for the Solid Phase Micro‐extraction of Malachite Green

A monolithic fiber of molecularly imprinted polymer (MIP) was prepared by in situ polymerization within the capillary with an inner diameter of 530 µm. It was carried out in 8 min by microwave irradiation using malachite green (MG) as a template molecule, α‐methacrylic acid (MAA) as a functional monomer, acetonitrile (ACN) as a porogenic solvent, ethylene dimethacrylate (EDMA) as a crosslinker, azodiiso‐butyronitrile (AIBN) as a thermal initiator. The resulted MIP fibers were pushed out from the capillary, eluted and inserted in the capillary again, which successfully used for the solid phase microextraction (SPME) procedure. The factors affecting the extraction of MG, such as the molar ratio of template/monomer (MG/MAA), concentration of NaCl, extraction and desorption time, and extraction and desorption solvents were investigated in detail. The selectivity of the MIP fibers was compared using MG analogues crystal violet (CV) and non‐analogue Sudan II. It was also employed for the pretreatment of trace MG in the fish feed followed by high‐performance liquid chromatography (HPLC) detection. Under the optimal conditions, the linear range of MG was 10‐600 μg/L, the detection limit (LOD) was 1.23 μg/L and the recovery of spiked fish feed sample was 88.7～113.9%.     

A novel polymerization of ultrathin sensitive imprinted film on surface plasmon resonance sensor

A new surface-initiated polymerization based on pasting the initiator on a sensor chip surface was applied to prepare a malachite green (MG) imprinted ultrathin film on a surface plasmon resonance (SPR) sensor. First, the initiator (2,2-azoisobutyronitrile) was pasted on the gold surface using polyvinyl chloride (PVC). The initiator-covered gold chip was then soaked in a pre-polymerization solution prepared by dissolving methacrylic acid (functional monomer), ethylene glycol dimethacrylate (cross-linker), and MG (template) in DMSO in a weighing bottle. Finally, the weighing bottle was placed in a vacuum oven and thermal-initiated polymerization was conducted at 60 °C for 16 h. This method was simple and time-saving compared with the commonly used surface-initiated polymerization. More importantly, the molecularly imprinted polymer (MIP) film prepared using this method was much thicker than that of commonly used methods; the adsorption quantity was also much larger. The MIP modified SPR sensor showed high sensitivity and selectivity as well as good stability in detecting MG. The results suggest that the ultrathin MIP film prepared using the new method in this study is suitable to serve as the recognition element of the SPR sensor.     

Synthesis of surface molecularly imprinted polymer and the selective solid phase extraction of imidazole from its structural analogs

A surface molecularly imprinted polymer (MIP) was synthesized by using imidazole as the template and modified silica particles as the support material. The static adsorption, solid phase extraction (SPE) and high-performance liquid chromatography (HPLC) experiments were performed to investigate the adsorption properties and selective recognition characteristics of the polymer for imidazole and its structural analogs. It was shown that the maximum binding capacities of imidazole on the MIP and the non-imprinted polymer (NIP) were 312 and 169 μmol g⁻¹, respectively. The adsorption was fast and the adsorption equilibrium was achieved in 30 min. The binding process could be described by pseudo-second order kinetics. Compared with the corresponding non-imprinted polymer, the molecularly imprinted polymer exhibited much higher adsorption performance and selectivity for imidazole. The selective separation of imidazole from a mixture of 1-hexyl-3-methylimidazolium bromide ([C₆mim][Br]) and 2,4-dichlorophenol could be achieved on the MIP-SPE column. The recoveries of imidazole and [C₆mim][Br] were 97.6-102.7% and 12.2-17.3%, respectively, but 2,4-dichlorophenol could not be retained on the column. The surface molecularly imprinted polymer presented here may find useful application as a solid phase absorbent to separate trace imidazole in environmental water samples. This may also form the basis for our research program on the preparation and application of alkyl-imidazolium imprinted polymers.     

安定分子印迹聚合物的制备及应用

以安定为模板分子,通过本体聚合和沉淀聚合的方法合成了分子印迹聚合物材料,考察了交联剂、致孔剂及温度等条件对聚合物材料性能的影响。电镜扫描图片显示本体聚合得到的聚合物呈不规则形状,而沉淀聚合得到的则是微球颗粒,形状规则。吸附实验表明,聚合物微球对安定的最大吸附量约为130μg/g,对奥沙西泮和硝西泮的吸附量约为110μg/g,对安定类化合物具有较高的吸附性能和选择性。通过对比合成现象和聚合物性能,最终选用以DVB为交联剂、乙腈为致孔剂合成的聚合物微球为固相萃取材料填充固相萃取小柱,从饲料及猪尿样品中选择性地分离、富集痕量安定类药物。结合高效液相色谱法检测,奥沙西泮、硝西泮和安定3种药物在0.1～20 mg/L范围内线性良好,相关系数为0.999 6～0.999 9,检出限(S/N=3)为0.03～0.08 mg/L,加标回收率为66%～79%。该方法为安定类药物的检测提供了一种新途径。     

Simultaneous preconcentration and determination of malachite green and fuchsine dyes in seafood and environmental water samples using nano-alumina-based molecular imprinted polymer solid-phase extraction

Molecular imprinted polymer for determination of malachite green (MG) and fuchsine basic (FU) dyes by spectrophotometry has been used, to develop a novel simultaneous extraction and preconcentration method. Molecularly imprinted layer-coated nano-alumina (MIP@Nano-Al₂O₃) as adsorbent was prepared by surface molecular imprinting technique, and characterised by FTIR spectroscopy, scanning electron microscopy, energy dispersive X-ray analysis (EDAX) and thermogravimetric analysis (TGA). The method is based on simultaneous extraction of MG and FU dyes from aqueous solution by using molecularly imprinted polymer and measuring the absorbance at 617 and 546 nm for MG and FU, respectively. Parameters which affect the extraction efficiency such as pH, volume of eluent and amount of adsorbent were investigated and optimised. Linear calibration curves were obtained in the range of 2–750 ng mL^?1 for MG and 1–240 ng mL^?1 for FU under optimum conditions. Detection limit based on three times the standard deviation of the blank (3S_b) was 0.655 and 0.245 ng mL^?1 (n = 10) for MG and FU, respectively. The relative standard deviation (RSD) for 100 ng mL^?1 of MG and FU was 2.35 and 3.06% (n = 7), respectively. The method was applied to the simultaneous determination of the dyes in different seafood and environmental water samples.     

Preparation and Adsorption Ability of Molecularly Imprinted Polymer Microspheres for Malachite Green

Molecularly imprinted polymer (MIP) microspheres were synthesized through precipitation polymerization using malachite green (MG) as template, methacrylic acid (MAA) as monomer, and trimethylolpropane trimethacrylate (TRIM) as cross-linker. The microsphere structure of MIP was characterized by IR spectroscopy and SEM. The influence of preparation conditions such as monomer and cross-linker dosages on the polymer absorption of MG in acetonitrile solution was also explored. Under the optimum synthesis conditions (0.25 mmol MG, 1.5 mmol MAA, 2.5 mmol TRIM, 40 mL acetonitrile), the prepared MIP microspheres have a binding capacity as high as 2000 µg g^?1 of MG with an imprinting factor of above 4.0. The result suggests that the prepared MIP microspheres are promising material for the selective extraction of MG in complicated matrix solutions.     

Molecular Imprinting of Cyclodextrin on Silica-Gel Support for the Stationary Phase of High-Performance-Liquid-Chromatography

By copolymerizing acryloyl cyclodextrin (CD) andN,N'-methylenebisacrylamide with vinylated silica-gel in the presence of a template in water,a thin layer of molecularly imprinted CD polymer was immobilized on a porous silica-gel support. This mechanically weak polymer was reinforced by the silica-gel andsuccessfully used as a stationary phase in high-performance-liquid-chromatography (HPLC). When L-Phe-L-Phe was the template, the polymer/silica-gel conjugate retainedL-Phe-L-Phe in the aqueous eluent more strongly than D-Phe-D-Phe. As expected, the D-Phe-D-Phe-imprinted polymer retained D-Phe-D-Phe more strongly than L-Phe-L-Phe. Selective separation of antibiotics was also achieved by thepolymer/silica-gel conjugate. Molecularly imprinted CD polymer, immobilizedon silica-gel, is an eminent stationary phase for HPLC in water.     

Preparation of a novel lysozyme molecularly imprinted polymer using uniformly sized functionalized poly(glycidyl methacrylate) microspheres as the matrix and its application to lysozyme purification

A novel lysozyme imprinted polymer based on uniformly sized functionalized poly(glycidyl methacrylate) microspheres has been synthesized in aqueous solution using the surface imprinting technique. The microspheres were modified with hydroxyl ethyl methacrylate to allow for the introduction of polymerizable double bonds, with β‐cyclodextrin and acrylamide being grafted onto the surface as functional monomers. The selective recognition properties of the resulting molecularly imprinted polymers (MIPs) were investigated by HPLC. Various factors were also investigated in terms of their influence on the retention behaviors of the imprinted polymers, including the pH and salt concentration of the mobile phase. The binding capability properties of the MIPs were evaluated, and the P_GMA/EDMA‐MIPs showed a high adsorption capacity for lysozyme. Furthermore, this MIP was used to separate and enrich lysozyme from egg whites. The results revealed that the lysozyme surface‐modified MIP could be used to efficiently separate and purify lysozyme from egg whites. Copyright © 2013 John Wiley & Sons, Ltd.     

HPLC imprinted-stationary phase prepared by precipitation polymerisation for the determination of thiabendazole in fruit

A molecularly imprinted polymer (MIP) tailored for the HPLC determination of the fungicide thiabendazole (TBZ) has been synthesised in one single preparative step by precipitation polymerisation in an acetonitrile/toluene co-solvent, using TBZ as template molecule, methacrylic acid as functional monomer and divinylbenzene-80 as crosslinker. The imprinted polymer particulates obtained were characterised by scanning electron microscopy and nitrogen sorption porosimetry. These analyses showed clearly that spherical polymer particulates (polymer microspheres) with narrow size distributions (average particle diameter approximately 3.5 microm) and well-developed pore structures had been produced. The imprinted microspheres were packed into a stainless steel HPLC column (50 x 4.6 mm id) and evaluated as an imprinted stationary phase. The imprinting effect was demonstrated clearly, i.e., the column was observed to bind TBZ selectively, and the effect of different chromatographic parameters (e.g., temperature, flow-rate and elution solvents) on TBZ retention/elution studied. Under optimised conditions, the TBZ-imprinted column was used for the HPLC-fluorescence (HPLC-F) determination of TBZ directly from orange (both whole fruit and juice), lemon, grape and strawberry extracts at low concentration levels in less than 15 min, without any need for a clean-up step in the analytical protocol.     

Water‐compatible halloysite‐imprinted polymer by Pickering emulsion polymerization for the selective recognition of herbicides

A water‐compatible molecularly imprinted polymer was prepared by Pickering emulsion polymerization using halloysite nanotubes as stabilized solid particles. During polymerization, we used 4‐vinylpyridine as monomer, divinylbenzene as cross‐linking agent, toluene as porogen, 2,2‐azobisisobutyronitrile as initiator, 2,4‐dichlorophenoxyacetic acid as template to form the oil phase, and Triton X‐100 aqueous solution to form the water phase. The halloysite nanotubes molecularly imprinted polymer was characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. Kinetic and equilibrium bindings were also employed to evaluate the adsorption properties of the imprinted polymer. The imprinted polymer showed better selectivity, more rapid kinetic binding (60 min) for 2,4‐dichlorophenoxyacetic acid in pure water compared with rebinding in toluene. The imprinted polymer was used as a sorbent to enrich and separate 2,4‐dichlorophenoxyacetic acid from water, and was detected by high‐performance liquid chromatography with UV detection.     

邻羟基苯甲酸分子印迹聚合物对于异构体的识别及色谱行为研究

采用分子印迹技术，以邻羟基苯甲酸（水杨酸）为模板分子，α-甲基丙烯酸 为功能单体，采用不同的交联剂和致孔剂，合成了用于分离羟基苯甲酸异构体的印 迹聚合物，并以高效液相色谱及平衡吸附的方法对聚合物进行了评价。实验结果表 明，以氢键为主要结合作用力的水杨酸印迹聚合物具有特定的空间识别位点，在弱 极性溶剂中对模板分子有较强的选择性，可以对官能团位置异构体进行很好地分离 。研究了以氢键为主要作用力所形成的分子印迹聚合物在色谱分离中的应用，并讨 论了流动相对分离的影响及印迹聚合物和客体分子的作用机制。     

Molecular Imprinting of Cyclodextrins Leading to Synthetic Antibodies

Molecularly imprinted cyclodextrins were applied to HPLC stationary phases forefficient recognition of nano-scaled guests in water. When cholesterol was usedas a template molecule, the imprinted polymer selectively retained this guest morestrongly and selectively than did non-imprinted polymer. The imprinting effect inthe retention behavior was consistent with previously reportedphysicochemical analyses.Immobilization of the imprinted cyclodextrin polymer on the surfaceof silica gel in water was also successful. The polymer-silica gel compositesobtained had sufficient physical strength, and were useful for HPLC stationary phases. Thesemolecularly imprinted polymers could recognize steroids, amino acid derivatives,dipeptides, and antibiotics. Moreover, we found that the enantio-selectivity towardthe template molecules was significantly promoted. This methodology has greatpotential for the recognition of large guest molecules in water, and can be analternative to affinity chromatography for the separation of bio-molecules.     

Pending templates imprinted polymers—hypothesis,synthesis, adsorption,and chromatographic properties

This is the first time when protein‐imprinted polymers are prepared with “pending templates.” The polymers were synthesized in the presence of a real sample (chicken egg white), rather than any known commercial proteins. Compared with a simultaneously synthesized nonimprinted control polymer, the polymers show higher adsorption capacity for abundant components (as “pending templates”) in the original sample. Chromatography experiments indicated that the columns made of the imprinted polymers could retain abundant species (imprinted) and separate them from those not imprinted. Thus, the sample could be split into dimidiate subfractions with reduced complexities. “Pending template imprinting” suggests a new way to investigate molecular imprinting, especially to dissect, simplify, and analyze complicated samples through a series of polymers just imprinted by the samples per se.     

活性自由基聚合法制备多壁碳纳米管表面槲皮素分子印迹聚合物及其应用

为了制备能有效分离富集药草中槲皮素的固相萃取柱,以丙烯酰胺(AM)修饰的碳纳米管为载体,三硫代碳酸酯(DBTTC)为可逆加成-断裂链转移剂(RAFT试剂),槲皮素为模板,甲基丙烯酸(MAA)为功能单体,乙二醇二甲基丙烯酸酯(EGDMA)为交联剂,乙腈为致孔剂,制备了槲皮素分子印迹聚合物,采用红外光谱、扫描电镜和热重分析对印迹材料进行表征,通过高效液相色谱(HPLC)研究聚合物的吸附性能和对底物的特异性识别能力。结果表明,通过活性自由基聚合法合成的多壁碳纳米管表面槲皮素分子印迹聚合具有更好的形态结构和吸附性能,且对槲皮素有很好的特异性识别能力。     

Synthesis and application of molecularly imprinted polymer on selective solid-phase extraction for the determination of monosulfuron residue in soil

A novel sample clean-up procedure using molecularly imprinted polymer as the solid-phase extraction material for the determination of monosulfuron residue in soil samples has been developed. The molecularly imprinted polymer (MIP) was synthesized by non-covalent method with monosulfuron as the template. The selectivity and affinity of the MIP was evaluated by equilibrium adsorption and HPLC experiments, which demonstrated that the MIP has specific affinity for the template. The template-MIP interaction was studied by investigating the influence of different mobile phases on the retention of the template, which provided basic knowledge for the selection of the washing and elution solutions in the molecularly imprinted solid-phase extraction (MISPE) process. The study indicated that polar organic solvents with hydrogen bonding abilities have stronger eluting strength for the monosulfuron. After the MISPE procedure, a clean baseline was obtained in the HPLC quantification analysis. The recoveries of the method using the combination of MISPE and HPLC were above 93% and the R.S.D. was less than 3.2% in the soil sample determinations. Low detection limit (0.08 microg g(-1), when defined as 3 times of the noise) was also obtained in the method evaluation study.     

Preparation and Recognition Properties of Vanillin‐Imprinted Polymers

Some new molecularly imprinted polymers (MIPs) were prepared by different protocols involving vanillin as the imprinted molecule, methacrylic acid (= 2‐methylprop‐2‐enoic acid; MAA) as the functional monomer, and ethylene glycol dimethacrylate (EGDMA = 2‐methylprop‐2‐enoic acid ethane‐1,2‐diyl ester) as the cross‐linking agent. The adsorption property of the imprinted polymers was studied by UV spectrophotometry and HPLC. The results indicated that the porogen solvent had a certain influence on the adsorption performance of the polymer. The vanillin‐imprinted polymer MIP₁ prepared with MeOH as porogen, exhibited advantageous characteristics, i.e., a high binding activity, a good selectivity, and a rapid adsorption equilibrium. The binding parameters studied by Scatchard analysis established that there are two types of binding sites in MIP₁. Finally, by packing an SPE column (SPE = solid‐phase extraction) with the polymer MIP₁, the vanillin was separated and enriched successfully by this sorbent from the samples of Vanilla fragrans and beer.     

Enantiomeric Resolution on L—Carnitine Selective Polymers Prepared by Molecular Imprinting

L-carnitine selective polymers were prepared by molecular imprinting using methacrylic acid as the functional monomer. The acid function of the monomer is expected to form hydrogen bond and ionic interactions with the amine function of the target molecule L-carnitine.The imprinted polymers were used as stationary phases in high-performance liquid chromatography (HPLC). It was shown that L-carnitine imprinted polymer exhibited a higher affinity to its template molecule,while the non-imprinted polymer had no affinity to the compounds tested. Racemic carnitine hydrochloride was efficiently resolved on the L-carnitine imprinted polymer, and the separation factor is 1.9.     

Novel surface modified molecularly imprinted polymer using acryloyl-β-cyclodextrin and acrylamide as monomers for selective recognition of lysozyme in aqueous solution

A novel protein imprinted polymer for selective recognition of lysozyme was obtained. Acryloyl-β-cyclodextrin, which offered hydrophilic exterior and hydrophobic cavity that were allowed to self-assemble with the template protein through hydrogen interaction and hydrophobic interaction, was synthesized and used as the functional monomer. Polymerization was carried out in the presence of acrylamide as an assistant monomer, which resulted in a new type of protein imprinted polymer. Langmuir adsorption model was employed to describe the isotherms, and maximum adsorption capacity was evaluated. The performance of such imprinted polymer was further demonstrated by high-performance liquid chromatography, and the results showed that the column packed with the lysozyme imprinted silica beads could effectively separate lysozyme from the mixture of lysozyme–cytochrome c, lysozyme–bovine serum albumin, lysozyme–avidin or lysozyme–methylated bovine serum albumin, which showed its high selectivity.