Synthesis of monodispersed molecularly imprinted polymer particles for high-performance liquid chromatographic separation of cholesterol using templating polymerization in porous silica gel bound with cholesterol molecules on its surface

Monodispersed molecularly imprinted polymer particles selective for cholesterol were prepared by the copolymerization of styrene and divinylbenzene in the presence of template silica gel particles (particle size: 5 μm; pore size: 10 nm) functionalized with cholesterol on the surface, followed by dissolution of the cholesterol-bonded silica gel with a NaOH aqueous solution. Transmission and scanning electron micrographs of the molecularly imprinted polymer (MIP) particles revealed good monodispersity and porous structure. The MIP particles were packed into a high performance liquid chromatographic column, and its recognition ability of cholesterol was evaluated using cholesterol, cholesterol esters and fatty acid methyl esters by comparison with the non-imprinted polymer (NIP) particles prepared from styrene and divinylbenzene without cholesterol. The MIP particles showed a high affinity for cholesterol and cholesterol esters (K(MIP)'/K(NIP)' > 5.7).     

硅胶表面扑灭津分子印迹材料的制备及性能表征

以扑灭津为模板分子,在甲苯溶液中经三步反应合成了基于硅胶表面修饰的分子印迹聚合物,并探讨了聚合物制备工艺,验证了聚合物的结构。红外1726cm-1指认印迹膜中的羰基特征峰,元素分析表明印迹材料含碳量18%,N2吸附实验表征印迹膜厚度为0.3nm。应用高效液相色谱-质谱考察了扑灭津和其它3种三嗪农药水溶液中的竞争吸附特性。研究表明:本法制备的表面印迹材料对4种三嗪类农药的吸附均优于参比材料。     

粉煤灰基氧氟沙星分子印迹聚合物的制备及其应用

以工业废料粉煤灰微球为基质,氧氟沙星 (OFL) 为模板分子,采用表面印迹法制备印迹材料MIP。通过紫外光谱法结合理论分析选择实验条件,并对该印迹材料结构、吸附行为进行研究。结果表明,该印迹材料对氧氟沙星具有良好的特异识别性和优良的亲和性。与以硅胶为载体制备的印迹聚合物相比,该材料吸附容量更高和印迹效果更好。将其作为固相萃取填料对鸡产品进行分离富集,与C18柱相比,分离富集效果更好。结合UPLC,对实际样品中氧氟沙星进行分析,回收率为82.0%-96.7%,相对标准偏差低于5.5%,可用于鸡产品中氧氟沙星分离分析。     

硅胶表面苯并噻吩分子印迹聚合物的分子识别与吸附性能

选用γ-氨丙基三乙氧基硅烷和α-甲基丙烯酸修饰的硅胶作为载体,以甲基丙烯酸为功能单体,二甲基丙烯酸乙二醇酯为交联剂,苯并噻吩为模板分子,合成一种具有选择性识别苯并噻吩分子的印迹聚合物。采用红外光谱、元素分析及N2吸附对其结构进行了表征,以模拟汽油通过静态吸附对其吸附性能进行了研究。结果表明,在硅胶载体表面成功地嫁接了多孔的分子印迹聚合物薄层。印迹聚合物对苯并噻吩具有良好的识别性能,对苯并噻吩的吸附动力学满足Langergren准一级反应动力学方程,吸附过程属于单分子层吸附。符合Langmuir吸附模型印迹聚合物对苯并噻吩的平衡吸附容量达57.4×10-3,而非印迹聚合物的吸附容量为33.1×10-3。印迹聚合物在经过多次再生后其吸附容量基本不变,从而为在汽油深度脱硫中有效脱除噻吩类硫化物提供了一种新技术途径。     

核-壳型赤藓红分子印迹聚合物的制备及吸附性能的评价

以氨基化修饰的SiO_2为内核,人工合成色素赤藓红为模板,甲醇/水为溶剂,4-乙烯基吡啶为功能单体,二甲基丙烯酸乙二醇酯为交联剂,偶氮二异丁腈为引发剂,采用表面印迹技术,制备核-壳型赤藓红分子印迹聚合物。通过红外光谱对其结构进行表征,并通过动力学吸附、等温饱和吸附和实际样品加标实验对其吸附性能进行评价。结果表明,核-壳型赤藓红分子印迹聚合物具有较快的吸附能力,在15min左右达到吸附平衡,有较好的吸附容量,能够从复杂的食品样品中选择性吸附模板,且回收可达85%。     

环丙沙星分子印迹聚合物的合成及识别性能研究

采用分子印迹技术合成了以环丙沙星为印迹分子,以甲基丙烯酸和4-乙烯基吡啶同时为功能单体的分子印迹聚合物。运用平衡结合实验研究了印迹聚合物的吸附特性和选择识别能力。Scatchard分析表明,在所研究的浓度范围内,分子印迹聚合物中形成了两类不同的结合位点。底物选择实验表明,这种聚合物对环丙沙星呈现高的选择结合能力。     

Preparation and evaluation of a macroporous molecularly imprinted hybrid silica monolithic column for recognition of proteins by high performance liquid chromatography

A novel type of macroporous molecularly imprinted hybrid silica monolithic column was first developed for recognition of proteins. The macroporous silica-based monolithic skeleton was synthesized in a 4.6 mm i.d. stainless steel column by a mild sol–gel process with methyltrimethoxysilane (MTMS) as a sole precursor, and then vinyl groups were introduced onto the surface of the silica skeleton by chemical modification of γ-methacryloxypropyltrimethoxysilane (γ-MAPS). Subsequently, the molecularly imprinted polymer (MIP) coating was copolymerized and anchored onto the surface of the silica monolith. Bovine serum albumin (BSA) and lysozyme (Lyz), which differ greatly in molecular size, isoelectric point, and charge, were representatively selected for imprinted templates to evaluate recognition property of the hybrid silica-based MIP monolith. Some important factors, such as template–monomer molar ratio, total monomer concentration and crosslinking density, were systematically investigated. Under the optimum conditions, the obtained hybrid silica-based MIP monolith showed higher binding affinity for template than its corresponding non-imprinted (NIP) monolith. The imprinted factor (IF) for BSA and Lyz reached 9.07 and 6.52, respectively. Moreover, the hybrid silica-based MIP monolith displayed favorable binding characteristics for template over competitive protein. Compared with the imprinted silica beads for stationary phase and in situ organic polymer-based hydrogel MIP monolith, the hybrid silica MIP monolith exhibited higher recognition, stability and lifetime.     

基于表面分子印迹技术及相转化过程的双酚A电化学传感器

以双酚A (Bisphenol A, BPA)为模板, 氨基化硅胶为载体合成了对BPA有特异选择性的表面分子印迹聚合物(surface molecularly imprinted polymer, sMIP). 然后以聚氯乙烯(PVC)为支撑基质, 通过相转化过程(phase inversion process)制成BPA分子印迹聚合物膜, 将聚合物膜固载到处理过的金电极表面, 制成电流型双酚A电化学传感器. 优化了pH值、温度等实验条件, 结果表明在10～120 μg/mL范围内对双酚A有良好的线性响应(R＝0.9971). 传感器用于实际水样的测定, 结果令人满意.     

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.     

表面分子印迹高分子膜修饰硅胶用于血清中茶碱的固相萃取

采用表面引发可逆加成-断裂链转移自由基聚合反应,在硅胶表面修饰了分子印迹高分子膜(MIP-silica)。以元素分析和氮吸附分析对修饰的分子印迹高分子膜进行了表征。与传统采用本体聚合合成的分子印迹高分子相比,MIP-silica具有更好的传质能力。本文合成的茶碱印迹MIP-silica可以作为选择性固相萃取材料从血清中富集、检测微量的茶碱,该法合成的MIP-silica还可用于高效液相色谱和毛细管电色谱等领域。     

Preparation and Characterization of Prometryn Molecularly Imprinted Solid‐Phase Microextraction Fibers

Abstract

A novel reproducible solid‐phase microextraction (SPME) coating was prepared on the surface of silanized silica fibers by molecularly imprinted polymerization using prometryn as template molecule. The structure and extraction performance of molecularly imprinted polymer (MIP) coating was studied with the scanning electron microscope and high performance liquid chromatography (HPLC). Specific selectivity was found with the prometryn MIP‐coated fiber to prometry and its structural analogues such as atrazine, simetryn, terbutylazin, ametryn, propazine and terbutryn. In contrast, these triazines could not be selectively extracted by the non‐imprinted polymer fiber or commercial polydimethylsiloxane (PDMS), polydimethylsiloxane/divinylbenzene (PDMS/DVB), polyacrylate (PA) fibers.     

A Novel Electrochemical Sensor for β2‐Agonists with High Sensitivity and Selectivity Based on Surface Molecularly Imprinted Sol‐gel Doped with Antimony‐Doped Tin Oxide

A novel strategy to improve the sensitivity of molecularly imprinted polymer (MIP) sensors was proposed for the determination of β₂‐agonists. The imprinted sol‐gel film was prepared by mixing silica sol with a functional monomer of antimony‐doped tin oxide (ATO) and a template of β₂‐agonists. ATO, which was embedded in the surface of the molecularly imprinted sol‐gel film, not only provides the excellent conductivity for biosensor but also increases the stability and the surface area of the MIP film. The imprinted sensor was characterised by field emission scanning electron microscope, fourier transform infrared spectroscopy and electrochemical methods. Under the optimal experimental conditions, the peak current was linear with the logarithm of the concentration of clenbuterol (CLB) in the range of 5.5 nM–6.3 µM, and a detection limit of 1.7 nM was obtained. Meanwhile, the electrochemical sensor showed excellent specific recognition of the template molecule among structurally similar coexisting substances. Furthermore, the proposed sensor was satisfactorily applied to determine β₂‐agonists in human serum samples. The good results indicated that highly effective molecularly imprinted sol‐gel films doped with ATO can be employed for other analytes.     

伊诺沙星分子印迹聚合物的制备及分子识别性能研究

以伊诺沙星为印迹分子、甲基丙烯酸为功能单体、季戊四醇三丙烯酸酯为交联剂,合成了对伊诺沙星有较好选择性的印迹聚合物。利用铽敏化荧光,通过静态平衡结合法和Scatchard分析法研究了此印迹聚合物的结合能力和选择性,结果表明印迹聚合物对伊诺沙星有较高的亲和性和选择性。     

Preparation of a novel molecularly imprinted polymer using a water-soluble crosslinking agent

A molecularly imprinted polymer was prepared using a water-soluble crosslinking agent. An ionic complex was utilized as the assembly for the template molecule and the functional monomer, and water as porogenic solvent during preparation of the imprinted polymer. The results of chromatographic evaluations for the prepared polymer suggested that the polymer had much lower hydrophobicity compared with usual octadecyl group bonded silica or the usual molecular imprinted polymer prepared from ethyleneglycol dimethacrylate, and the selective recognition ability for template molecule in the completely aqueous condition.     

Extraction of crocin from saffron (Crocus sativus) using molecularly imprinted polymer solid‐phase extraction

A new molecularly imprinted polymer for extraction of crocin from saffron stigmas was prepared using gentiobiose (a glycoside moiety in crocin structure) as a template. Crocin binding to gentiobiose imprinted polymer (Gent‐MIP) was studied in comparison with a blank nonimprinted polymer in aqueous media. Affinity of the Gent‐MIP for the crocin was more than the nonimprinted polymer at all concentrations. In Scatchard analysis, the number of binding sites in each gram of polymer (maximum binding sites) and dissociation constant of crocin to binding sites were 18.4 μmol/g polymer and 11.2 μM, respectively. The Gent‐MIP was then used as the sorbent in an SPE method for isolation and purification of crocin from methanolic extract of saffron stigmas. The recovery of crocin, safranal and picrocrocin was determined in washing and elution steps. The Gent‐MIP had significantly higher affinity for crocin than other compounds and enabled selective extraction of crocin with a high recovery (84%) from a complex mixture. The results demonstrated the possibility of using a part of a big molecule in preparing a molecularly imprinted polymer with a good selectivity for the main structure.     

Analytical followup of the gamma initiated synthesis of a molecularly imprinted polymer

A molecularly imprinted polymer (MIP) for the template phenytoin has been prepared by gamma initiated copolymerization of methacrylamide and ethylene glycol dimethacrylate. The progress of polymerization was studied by measuring the monomer conversions and the template binding properties of the resulting polymers, respectively. The consumption rate of the two monomers showed different course. There was no difference observed in the polymerization rates of the MIP and the control polymer (NIP). The template binding properties of the MIP and the NIP changed considerably with the progress of the polymerization process and became similar to those of the thermally initiated polymers after full conversion.     

Photoregulated uptake and release of drug by an organic–inorganic hybrid sol–gel material

A photo-responsive molecularly imprinted sol–gel organic-inorganic hybrid material prepared by covalent imprinting of the template-functional monomer complex formed between 4,4′-dihydroxylazobenzene and ibuprofen was developed to explore the photo-regulated uptake and release of drug by a silicate-based smart molecularly imprinted materials. After imprinting, the template molecules (ibuprofen) were removed via hydrolysis in acid, and accurate cavities were left, which could be used as the receptor recognition sites for ibuprofen. The new organic–inorganic hybrid material shows specific affinity to ibuprofen and reversible uptake and release of ibuprofen upon alternate irradiation at 365 and 440 nm, respectively. The favorable binding strength of the imprinted receptor sites in the molecularly imprinted polymer (MIP) for ibuprofen is found to be 2.28 × 10³ M⁻¹. Density of receptor sites in the MIP material was 4.0 μmol/g—MIP.     

Evaluation of a novel silica-supported sol–gel sorbent prepared by a surface molecular imprinting technique for the selective separation of estazolam from human plasma

A molecular imprinting polymer (MIP) based on surface modification of silica gel was prepared via the sol–gel process with 3-aminopropyltriethoxysilane and phenyltrimethoxysilane as functional monomers, and estazolam as the template. The imprinted silica sorbent was characterized by Fourier Transform Infrared Spectroscopy, surface elemental analysis, and scanning electron microscopy (SEM). An MIP of agglomerated nano-particles with multi-pores was grafted onto the surface of the silica gel after hydrolytic condensation of the siloxane. The imprinted silica sorbent was used for solid phase extraction (SPE). Using water as loading solvent, the extraction efficiency for estazolam was higher compared to the use of an organic solvent. The imprinted silica sorbent was selective not only for the template, but also for the analogue. Compared to C₁₈-SPE and liquid–liquid extraction, the MIP-SPE was the most feasible technique for extraction of estazolam from human plasma; up to 98.7?±?1.2% recovery was achieved.     

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.     

尼卡地平分子聚合物的制备及识别性能研究

采用分子印迹技术合成了以尼卡地平为模板分子,甲基丙烯酸为功能单体的分子印迹聚合物(MIP).运用平衡结合实验研究了聚合物的吸附特性和选择识别能力.通过Scatchard方程分析,结合位点的离解常数Kd=1.03 mmol·L-1,最大表观结合常数Qmax=18.76 μmol·g-1.结果表明,分子印迹聚合物对尼卡地平呈现出较高的吸附性和选择识别性,对尼卡地平药物的分离富集和检测具有实际临床意义.