悬浮聚合法制备磁性分子印迹聚合物微球

以苯胺和二甲基苯胺为模板分子、甲基丙烯酸(MAA)为功能单体、三羟甲基丙烷三丙烯酸酯(TRIM)为交联单体、Fe3O4为磁性组分,采用悬浮聚合法制备了磁性分子印迹聚合物微球(MMIPMs)。结果表明,改性Fe3O4微粒在MMIPMs中分散较好,MMIPMs在水性介质中对模板分子的选择吸附性较差,但在有机介质中有较好的选择吸附性。     

核壳结构的萘夫西林磁性分子印迹聚合物微球的制备及性能

以表面修饰双键的Fe₃O₄@SiO₂纳米颗粒为基体,以萘夫西林(nafcillin)为模板,甲基丙烯酸(MAA)为单体,乙二醇二甲基丙烯酸酯(EGDMA)为交联剂,偶氮二异丁腈(AIBN)为引发剂,采用三步升温聚合法合成了核壳结构的萘夫西林磁性分子印迹聚合物。采用傅里叶变换红外光谱仪(FT-IR)、透射电子显微镜(TEM)、X射线衍射仪(XRD)和振动样品磁强计(VSM)对制备的印迹聚合物微球进行了表征,得到的磁性印迹聚合物微球的粒径在320 nm左右,大小均匀,分散性较好,可以在外加磁场下与溶剂实现快速分离。对磁性印迹和非印迹聚合物进行了吸附性能研究,结果表明该印迹聚合物微球对模板分子具有很高的吸附容量(50.7 mg/g),特异性识别性能良好(印迹因子为2.46),有望应用于实际样品中萘夫西林残留量的富集分析。     

活性/可控自由基聚合制备恩诺沙星印迹微球及识别性能研究

研究了一种以活性／可控自由基聚合（可逆加成一断裂链转移自由基聚合,reversible addition-fragmentation chain transfer radical polymerization,RAFT polymerization）制备分子印迹微球的方法。结合沉淀聚合法,以二硫代苯甲酸异丙苯酯（cumyl dithiobenzoate,CDB）为可逆加成一断裂链转移剂,恩诺沙星为印迹化合物,甲基丙烯酸（MAA）和乙二醇二甲基丙烯酸酯（EDMA）分别为功能单体和交联剂,偶氮二异丁腈（AIBN）为引发剂,乙腈为分散剂,考察了温度、单体浓度等反应条件对微球制备的影响。通过改变AIBN和CDB的比例,可以达到控制分子印迹微球粒径和分散性的目的。扫描电镜结果显示,以RAFT聚合法得到的分子印迹微球粒径可达2．0～2．2μm,并有良好的分散性。平衡吸附实验结果说明印迹聚合物微球对印迹化合物的结合能力优于非印迹聚合物。分子印迹微球对于恩诺沙星及其结构类似物洛美沙星的饱和吸附量分别为37．3和19．5μmol·g^-1,证明分子印迹微球有很好的识别能力。     

核-壳型苏丹红Ⅰ印迹聚合物微球制备及应用研究

以苏丹红Ⅰ为模板分子,苯基-三甲氧基硅烷(PTMOS)为功能单体,乙二醇二甲基丙烯酸酯(EGD-MA)为交联剂,偶氮二异丁腈(AIBN)为引发剂,采用表面分子印迹技术,在自制的SiO2微球表面成功合成了对苏丹红Ⅰ具有良好选择识别性能的核-壳型印迹聚合物。采用红外光谱和扫描电子显微镜对分子印迹微球进行表征,结果表明该印迹聚合材料壳层厚度约为150 nm;采用静态吸附实验研究印迹材料对模板聚合物的吸附性能和选择特性,结果表明以PTMOS为功能单体的印迹聚合物对苏丹红Ⅰ具有优异的选择吸附性,其分离选择因子为2.62。在吸附过程中,模板分子苏丹红Ⅰ与印迹聚合物形成2种结合位点,2种结合位点的解离常数分别为2.30、10.78 mmol/L,最大表观结合量分别为27.40、128.53μmol/g。将该印迹聚合物作为固相萃取材料,对样品进行固相萃取,结合液相色谱技术成功用于辣椒油中苏丹红Ⅰ的测定。     

基于金属卟啉的甲基磷酸二甲酯分子印迹聚合物微球的合成及性能

合成了分别以5-(4-甲基丙烯酰氧苯基)-10,15,20-三苯基锌卟啉(ZnMOTPP)和5-(4-甲基丙烯酰氧苯基)-10,15,20-三苯基钆卟啉(GdMOTPP)为功能单体, 甲基丙烯酸(MAA)为辅助功能单体的甲基磷酸二甲酯(DMMP)分子印迹聚合物微球. 扫描电子显微镜(SEM)表征结果表明, 微球平均粒径为50～100 μm, 粒度均匀. 与甲基丙烯酸作为功能单体的分子印迹聚合物微球的吸附性能和特异性进行对比发现, ZnMOTPP分子印迹微球的吸附性能优于 GdMOTPP分子印迹微球, 金属卟啉分子印迹微球的吸附性能优于仅以甲基丙烯酸作为功能单体的分子印迹微球, 并且微球对其印迹分子DMMP具有特异性吸附. Scatchard分析表明, DMMP分子印迹空穴中只存在一类结合位点, MIPMs-Zn+MAA的最大吸附量Q_max=148 μmol/g, MIPMs-Gd+MAA的Q_max=78.9 μmol/g, MIPMs-MAA的Q_max=13.57 μmol/g.     

两步蒸馏沉淀聚合法制备红霉素表面分子印迹聚合物及其性能研究

采用两步蒸馏沉淀聚合法,制备了红霉素表面分子印迹聚合物.第一步制备了甲基丙烯酸和二乙烯基苯共聚物微球(PMAA-co-DVB),将其作为内核,再通过第二步蒸馏沉淀聚合,以甲基丙烯酸(MAA)为功能单体,二乙烯基苯(DVB)为交联剂,偶氮二异丁腈(AIBN)为引发剂,红霉素(EM)为模板分子,内核表面聚合一层分子印迹膜层,从而制得具有"核-壳"结构的红霉素表面分子印迹聚合物.通过激光粒径测定、扫描电子显微镜以及结合实验对其形貌和结合性能进行表征.结果表明,在聚合物单体体积分数为7%时,制备出的PMAA-co-DVB微球形态良好,当EM与MAA的比例为1∶4,第二步蒸馏沉淀聚合中单体体积分数为2.8%时,所得的印迹材料结合性能最佳,对EM最大结合量为76.8 mg/g,结合达到平衡的时间为90 min.对红霉素的识别能力高于对其结构类似物罗红霉素.     

多壁碳纳米管表面过氧化苯甲酰印迹复合材料的制备及固相萃取应用

以过氧化苯甲酰(BOP)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(EGDMA)为交联剂,偶氮二异丁腈(AIBN)为引发剂,采用热聚合法在多壁碳纳米管(MWNTs)表面制备印迹聚合物(MWNTs-MIPs)。采用红外和热重分析等技术对聚合物结构进行表征。采用液相色谱考察该分子印迹聚合物对过氧化苯甲酰的吸附特性。结果表明该印迹聚合物对过氧化苯甲酰表现出特异性吸附,该印迹聚合物对模板分子存在一种结合位点,其最大表观结合量为56.20 µmol/g。该印迹聚合物成功应用于固相萃取富集面粉中微量过氧化苯甲酰,浓度富集因子为526。     

分子印迹聚合物选择性富集长春碱的研究

分子印迹聚合物(MIPs)是近年来发展起来的一种对特定分子(模板分子)具有高度选择性的合成高分子材料.本文以长春碱(VLB)为模板分子,以甲基丙烯酸(MAA)为功能单体、乙二醇二甲基丙烯酸酯(EGDMA)为交联剂,在偶氮二异丁腈(AIBN)的引发下制备了长春碱印迹聚合物(VLB-MIP).采用紫外光谱对VLB与MAA之间形成的模板-功能单体复合物进行了分析,通过扫描电镜(SEM)对制备的VLB-MIP的表面形态进行了表征,并用BET法对MIP表面的孔径进行了测定.结果表明,VLB-MIP与未加模板分子制备的非印迹聚合物(NIP)相比表面多孔、粗糙,比表面积显著增加.以VLB-MIP作为固相萃取(SPE)的吸附剂,对VLB-MIP的选择性进行了评价,VLB-MIP能特异性地吸附VLB,而对VLB的结构类似物长春新碱(VCR)却没有表现出明显的吸附行为.将长春花提取物上样于填充VLB-MIP的SPE柱上,在最优实验条件下,长春花提取物中的VLB能被高效富集.此外,上样溶剂对MIP柱的吸附容量有影响,长春花提取物溶于非极性溶剂甲苯时,MIP的吸附容量最大为750μg/g,其次是氯仿吸附容量为625μg/g,最小的是甲醇为250μg/g.     

选择性富集分离虎杖中白藜芦醇苷的分子印迹聚合物的制备及分子识别性能研究

以白藜芦醇苷(POL)为模板分子,分别以丙烯酰胺(AM)、4-乙烯基吡啶(4-VP)、甲基丙烯酸羟乙酯(HEMA)、甲基丙烯酸(MAA)为功能单体,二甲基丙烯酸乙二醇酯(EGDMA)为交联剂,偶氮二异丁腈(AIBN)为引发剂,采用本体聚合法制备白藜芦醇苷分子印迹聚合物。采用静态平衡结合实验研究了印迹聚合物对模板分子及不同底物的识别性能。结果表明,以丙烯酰胺为功能单体的印迹聚合物(MIP1)对模板分子的识别性能最好,其次是以4-VP为功能单体的聚合物(MIP2),以HEMA为功能单体的聚合物(MIP3)以及以MAA为功能单体的聚合物(MIP4)的分子识别性能较差。表明功能单体与模板分子之间相互作用的强弱对MIP的识别能力有较大的影响。静态平衡结合法以及Scatchard分析法表明,MIP1对模板分子呈现较好的结合能力和选择性,该印迹聚合物中形成了2类不同的结合位点,离解常数分别为7.43×10-5、3.70×10-3mol/L。将MIP1用于虎杖提取物中POL的固相萃取分离,效果良好。     

高性能胰蛋白酶分子表面印迹材料的制备及其大分子识别特性研究

以交联聚乙烯醇(CPVA)微球为基质,以甲基丙烯酸(MAA)为功能单体,在中性水介质中制备了高性能胰蛋白酶(TRY)大分子表面印迹材料。首先通过CPVA微球表面的羟基与甲基丙烯酰氯之间的酯化反应,将大量可聚合双键甲基丙烯酰基(MAO)引入微球表面,获得改性微球MAO-CPVA。在中性水溶液中,单体MAA的羧基几乎发生完全电离,凭借强烈的静电相互作用,MAA自动结合在碱性蛋白TRY大分子周围,形成单体-模板复合体。水溶液中过硫酸铵/亚硫酸氢钠引发体系所产生的自由剂,使包围在TRY周围的单体MAA与交联剂N,N'-亚甲基双丙烯酰胺(MBA)在微球MAO-CPVA表面发生接枝交联聚合,而模板TRY则被包裹在交联网络之中,除去模板后便得到了TRY表面印迹微球MIP-PMAA/CPVA。深入考察了该表面印迹微球的大分子识别性能。研究结果表明,表面印迹微球MIP-PMAA/CPVA对TRY具有优良的结合亲和性,结合容量高达84mg·g~(-1)(3.6μmol·g~(-1));对模板蛋白TRY具有特异的识别选择性,相对于另一种碱性蛋白木瓜蛋白酶,印迹微球对TRY的选择性系数高达21.62。     

左旋甲基多巴分子印迹纳米给药系统的合成、表征及药物缓释研究

采用沉淀聚合法合成了左旋甲基多巴(L-Methyldopa, LMD)分子印迹聚合物微球(MIPMs), 并对其合成条件进行了详细研究. 结果表明, 聚合温度和引发剂的用量对微球的大小和形态有较大的影响, 微球的粒径随聚合温度的降低而增大, 随偶氮二异丁睛(AIBN)量的增大而增大. 而模板分子似乎对微球粒径的影响不是很明显. 通过扫描电镜、静态吸附试验(BET)和斯卡查德分析(Scatchard analysis)、红外光谱分析和模拟人体胃液扩散实验等对微球的外貌形态、吸附性能、分子印迹效果和药物缓释效果进行了表征. BET吸附实验和Scatchard 分析结果表明, 分子印迹聚合微球(MIPMs)的最大静态吸附量是非印迹聚合物微球(NIPMs)的3倍. 药物扩散实验表明, LMD在非印迹微球(NIPMs)上的释药率几乎与时间呈直线关系, 说明其释药过程完全受扩散控制; 而LMD在MIPMs上的释药率则呈曲线上升趋势, 说明其释药过程除了受扩散控制外, 还受到药物模板分子与MIPMs之间的印迹效应的协同作用的控制, 从而达到了缓释药物分子的目的. 实验结果表明, 在模拟胃液中, MIPMs释放药物的持续时间(10 h)是NIPMs持续时间(5 h)的2倍, 表明分子印迹微微球确实具有缓释药物的效果. 因此, MIPMs有望进一步应用于LMD药物缓释系统的研究.     

Adsorption of carbaryl using molecularly imprinted microspheres prepared by precipitation polymerization

To obtain the desired specific adsorbents for carbaryl to enrichment, separation, and analysis of trace pesticide residues in environmental water, molecularly imprinted polymer (MIP) microspheres were prepared by precipitation polymerization using carbaryl, methacrylic acid (MAA), ethylene glycol dimethacrylate (EGDMA), azobisisobutyronitrile (AIBN), and acetonitrile as template, functional monomer, cross‐linker, initiator, and porogen, respectively. Molecular modeling software was used to compute rational interaction between the template molecule and function monomer. The adsorption properties of carbaryl in acetonitrile for imprinted microspheres were evaluated by equilibrium rebinding experiments. Scatchard plot analysis revealed that there was one class of binding sites populated in the imprinted polymer microspheres with dissociation constants of 3.3 × 10^?2 mol/l and an apparent maximum number of 1.95 µmol/g. The specificity of the imprinted microspheres was investigated by binding analysis using carbaryl and structurally related carbamate pesticides. The results indicated that the obtained imprinted microspheres showed a good selectivity for carbaryl. Copyright © 2007 John Wiley & Sons, Ltd.     

农药久效磷分子印迹聚合物合成及其亲合性评估

有机磷农药药效高、易于被水、酶和微生物所降解，残留毒性小，但由于不合理利用等因素，粮食、蔬菜、水果和环境中的有机磷农药残留严重超标，其危害引起了各国政府、学术界、民众的高度重视．目前有色谱法、酶法和免疫法等，这些方法的应用都受到客观因素的限制．因此研制类似于酶和抗体的高选择性、低造价、稳定性好的吸附材料用于食品和环境中有机磷农药残留的富集、分离纯化和分析尤为重要．     

Preparation and characterization of molecularly imprinted microspheres for selective extraction of trace melamine from milk samples

We describe molecularly imprinted microspheres (MIMs) for the selective extraction of melamine from milk. The MIMs were made from melamine as the template molecule, methacrylic acid as the functional monomer, and ethylene glycol dimethacrylate as the linking agent. The MIMs were synthesized by suspension polymerization and characterized by rebinding experiments. They displayed high adsorption capacity, fast rebinding kinetics, and highly specific rebinding of melamine. The imprinting factor is 4.1. Scatchard analysis revealed a one-type rebinding behavior, the dissociation constant and maximum rebinding capacity being 37.59 g L^?1 and 30.85 μmol g^?1, respectively. The MIMs exhibited a 25% cross-reactivity towards atrazine, but less than 3.0% towards prometryn, clenbuterol and metronidazole. In addition, a MIM-based solid phase extraction (MISPE) column for melamine was prepared by packing MIMs into a common SPE cartridge. The MISPE extraction gave recoveries of 89.8 to 100.6% of melamine, with relative standard deviations of 5.9 to 7.5%. There was no significant loss of rebinding capacity after more than 60 repeated uses, thus demonstrating the high stability of the MISPE column. The MSPE column also was applied to the extraction of melamine from spiked liquid and powdered milk with satisfying accuracy and precision.

Fabrication of Atrazine Molecularly Imprinted Polymer Microsphere by Two Step Seed Swelling Polymerization Method

Atrazine molecularly imprinted polymer microspheres (MIPMs) were fabricated by two step seed swelling polymerization method, using atrazine as a template molecule, methacrylic acid (MAA) as a functional monomer, ethylene glycol dimethacrylate (EDMA) as a crosslinking agent and toluene/dodecanol as a porogenic agent and a series of MIPMs with even particle size of 3‐5 μm and good dispersivity could be obtained under the optimal condition. Equilibrium binding experiments were comparably studied about the binding capacity of the resulted polymers. We packed the polymers into empty chromatographic steel tube columns (2.1 mm I.D. × 10 cm) to prepare liquid chromatographic columns used for the evaluation of specificity with similar structure compounds. The proposed method has been successfully applied to the determination of limited atrazine in water samples. The results showed that a good linear relationship of atrazine was maintained within 0.1‐20 mg/L (r = 0.9992), the sample recovery was in a range of 92.1‐102.0%, with a RSD lower than 5% (n = 6) and a detection limit of 0.041 mg/L.     

邻苯二甲酸二异辛酯表面印迹聚合物的制备及其固相萃取应用

采用复合二氧化硅微球(H-SiO2)作为载体,以邻苯二甲酸二异辛酯(DIOP)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(EGDMA)为交联剂,制备了邻苯二甲酸二异辛酯表面印迹聚合物(H-SiO2@MIP)。 分别采用扫描电子显微镜和红外光谱对该印迹聚合物进行了观察和表征,结果表明,制备出的印迹聚合物呈球形,印迹壳层厚度为60~70 nm。 采用高效液相色谱技术对该印迹聚合物的吸附性能进行了检测,结果表明,该印迹聚合物对塑化剂DIOP表现出特异性吸附性能,最大吸附容量为50.35 mg/g,DIOP对于邻苯二甲酸二丁酯(DBP)和邻苯二甲酸二乙酯(DEP)的选择因子(β)分别为2.31和2.47。 将该印迹聚合物装填于固相萃取柱中,结合液相色谱检测技术,能对牛奶样品中的塑化剂DIOP进行有效分离、富集和检测。     

Synthesis and evaluation of molecularly imprinted polymeric microspheres for highly selective extraction of an anti-AIDS drug emtricitabine

The molecularly imprinted polymeric microspheres (MIPMs, 3～5 μm), used as high-performance liquid chromatography (HPLC) and solid-phase extraction (SPE) packing materials for anti-AIDS drug emtricitabine (FTC), were synthesized by precipitation polymerization. The effects of ratio of chloroform to acetonitrile on the morphology and diameter of MIPMs were investigated. The prepared MIPMs were characterized by HPLC. The imprinting factor (2.26) suggests that the resultant MIPMs exhibit good recognition and affinity to FTC. In addition, the MIPMs were used in SPE as packing material for separation and enrichment of FTC. The recovery of FTC on MIPMs cartridge was 97.6 % in standard solution. Finally, the MIPMs cartridge was applied to extract the FTC in human serum samples. Impurities in sample have been mostly removed, and the average recovery of 92.5 % was obtained with a detection limit of 0.005 μg/mL and a linear range of 0.02～4.0 μg/mL. The method established can be used to monitor the FTC in human serum sample with good accuracy and selectivity.     

Metal‐imprinted microsphere prepared by surface template polymerization and its application to chromatography

A metal ion‐imprinted microsphere was prepared by surface molecular template polymerization. Trimethylolpropane trimethacrylate (TRIM), zinc ions, 1,12‐dodecanediol‐O, O′‐diphenyl phosphonic acid (DDDPA) were used as a crosslinking agent, an imprint molecule, and a functional host molecule. The Zn(II)‐imprinted microspheres, which are spherically well‐defined particles, were prepared by using water‐in‐oil‐in‐water (W/O/W) multiple emulsions. The combination of TRIM and DDDPA serves to align the recognition sites resulting in better template sites produced on the polymer surface. We firstly conducted diagnostic zinc‐ and copper‐ion adsorption tests with the Zn(II)‐imprinted and unimprinted microspheres in order to make an assessment on the effectiveness of the molecular imprinting technique. Further, the metal‐imprinted microspheres were applied to the column operation. The separation and recovery of metals were carried out by an adsorption column packed with the Zn(II)‐imprinted microspheres. This performance was compared to that of commercial chelating resins that possess similar phosphoric functional groups. The Zn(II)‐imprinted polymer shows an extremely high selectivity to the imprinted zinc ions compared to that of the commercial chelating resin. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 689–696, 2000     

Determination of tetracyclines in food samples by molecularly imprinted monolithic column coupling with high performance liquid chromatography

A novel solid phase extraction (SPE) method for determination of tetracyclines (TCs) in milk and honey samples by molecularly imprinted monolithic column was developed. Using tetracycline (TC) as the template, methacrylic acid (MAA) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker, methanol as the solvent, cyclohexanol and dodecanol as the mixed porogenic solvents, a TC imprinted monolithic column was prepared by in situ molecular imprinting technique for the first time, and the optimal synthesis conditions and the selectivity of TC imprinted monolithic column were investigated. The interfering substances in food samples and TCs can be separated successfully on imprinted column. Molecularly imprinted solid phase extraction (MISPE) coupling with C18 column was used to determinate the TCs in milk and honey. The recoveries of this method for six tetracyclines antibiotics such as tetracycline (TC), oxytetracycline (OTC), minocycline (MINO), chlortetracycline (CTC), metacycline (MTC) and doxycycline (DTC) were investigated, and high recoveries of 73.3-90.6% from milk samples and 62.6-82.3% from honey samples were obtained. A method for determination of TCs at low concentration level in milk and honey samples was successfully developed by using the monolithic column as the precolumn for solid phase extraction of six TCs compounds.