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三聚氰胺分子印迹整体柱识别性能的研究 总被引:1,自引:0,他引:1
以三聚氰胺(MAM)为模板分子,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,原位聚合法制备了对MAM有很强选择性识别能力的分子印迹整体柱。采用脉冲洗脱法快速筛选MAM的洗脱剂,通过前沿色谱法测定了整体柱对MAM的结合容量。实验表明,所制备的印迹整体柱对MAM有极强亲和作用力,即使在强极性流动相中(甲醇或甲醇-水(V/V=80/20)),MAM在印迹柱上也有强保留,不被洗脱。实验测得结合位点数(Lt)和解离常数(Kd)分别为:印迹柱Lt=2.28×103μmol/g,Kd=2.45×10-5mol/L;空白柱Lt=366μmol/g,Kd=23.7mo/L。该印迹整体柱有望作为固相萃取柱,在线或离线选择性富集样品中的MAM。 相似文献
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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. 相似文献
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4-氨基吡啶分子印迹聚合物毛细管整体柱的制备及电色谱性能研究 总被引:10,自引:0,他引:10
以4-氨基吡啶(4-AP)为印迹分子,热引发原位合成了分子印迹聚合物毛细管整体柱,聚合物通过共价键和石英毛细管内壁相连,制备方法简单、快捷.在最佳电色谱条件下,4-AP和2-AP之间的分离度在印迹聚合物柱上高达2.5,而在不含印迹的对照柱上仅为0.35.通过研究流动相条件对4-AP,2-AP和硫脲迁移的影响,对4-AP印迹聚合物的电色谱识别机理进行了探讨.印迹识别能力随缓冲溶液离子强度的减小或流动相中乙腈比例的增大而增大.上述两种情形下,流动相中阳离子浓度均减少,使得聚合物孔穴中可与4-AP发生静电作用的有效羧基作用位点增加,从而显现出孔穴对印迹分子的专一亲和作用(形状、大小和作用力).缓冲溶液的种类和pH值对该印迹聚合物识别能力的影响较为复杂,在磷酸盐缓冲溶液体系中,pH值对识别能力的影响呈抛物线形,pH=5时识别能力最强;在醋酸盐缓冲溶液体系中,高pH值有利于分离. 相似文献
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The classification and regression trees (CART) possess the advantage of being able to handle large data sets and yield readily interpretable models. A conventional method of building a regression tree is recursive partitioning, which results in a good but not optimal tree. Ant colony system (ACS), which is a meta-heuristic algorithm and derived from the observation of real ants, can be used to overcome this problem. The purpose of this study was to explore the use of CART and its combination with ACS for modeling of melting points of a large variety of chemical compounds. Genetic algorithm (GA) operators (e.g., cross averring and mutation operators) were combined with ACS algorithm to select the best solution model. In addition, at each terminal node of the resulted tree, variable selection was done by ACS-GA algorithm to build an appropriate partial least squares (PLS) model. To test the ability of the resulted tree, a set of approximately 4173 structures and their melting points were used (3000 compounds as training set and 1173 as validation set). Further, an external test set containing of 277 drugs was used to validate the prediction ability of the tree. Comparison of the results obtained from both trees showed that the tree constructed by ACS-GA algorithm performs better than that produced by recursive partitioning procedure. 相似文献
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采用紫外光谱法选择丙烯酰胺为功能单体,以二苯甲酰-D-酒石酸(D-DBTA)为模板分子,丙烯酰胺为功能单体,二甲基丙烯酸乙二醇酯为交联剂,甲苯和十二醇为混合致孔剂,用原位分子印迹技术,合成了D-DBTA分子印迹整体聚合物。在优化色谱条件的基础上,25min内基本实现了DBTA消旋体的手性分离,分离度达1.25。对色谱分离过程中的热力学进行分析,在所考察的温度范围内,色谱分离存在两种不同的热力学过程,且两者与范特霍夫方程能够很好地吻合。在这两种热力学过程的转换温度处,分离因子α达最大值。 相似文献
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Molecular crowding is a new approach to promoting molecular imprinting more efficiently. In this work, this concept was applied to the preparation of low cross-linked imprinted polymers in the presence of an immobilised template for stabilizing binding sites and improving molecular recognition. An imprinted monolithic column was synthesized using a mixture of 2,4-diamino-6-methyl-1,3,5-triazine (template), 2,4-diamino-6-(methacryloyloxy) ethyl-1,3,5-triazine (polymerisable template), methacrylic acid, ethylene glycol dimethacrylate, and polystyrene (molecular crowding agent). Some polymerization factors, such as template-monomer molar ratio, the composition of the porogen and crosslinking density, on the imprinting effect of resulting MIP monolith were systematically investigated. The results indicated that the imprinted monolithic columns prepared in the presence of molecular crowding agent retained affinity and specificity for template even when prepared with a level of cross-linker as low as 9%. Moreover, a stoichiometric displacement model for retention was successfully applied to evaluate the interaction between the solute and the stationary phase. Compared with the low cross-linked MIP prepared by conventional polymerization, the molecular crowding-based low cross-linked monolithic MIPs showed higher selectivity. The results suggested that molecular crowding is a powerful strategy to increase the effect of molecular imprinting at a low level of crosslinker. 相似文献
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A novel prepared method of molecularly imprinted monolithic polymers (MIPs) using 4-hydroxybenzoic acid (4-HBA) as templates for capillary electrochromatography (CEC) was developed. A strategy of high concentration of monomers in the pre-polymerization mixture was used to fulfil the solubility of polar imprinted molecule and reduction of the interference during complex formation. The imprinted polymer capillary monolithic column was synthesized by an in situ therm-initiated copolymerization of methacrylic acid (MAA) and ethylene glycol dimethacrylate with a mixture of toluene-isooctane as a porogenic solvent in the presence of a polar model imprinting molecule, 4-HBA. On the resultant MIP monolithic column, the effect of parameter of CEC on electroosmotic flow (EOF) and the retention of 4-HBA was investigated. The column efficiency of the imprinted molecule, 4-HBA, was 13,000 plates/m. The resolution of isomers of HBA was 5.0 and good molecular recognition was achieved for 4-HBA. 相似文献
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A polymethacrylate‐based molecularly imprinted monolithic column bearing mixed functional monomers, using non‐covalent imprinting approach, was designed for the rapid separation of nitroimidazole compounds. The new monolithic column has been prepared via simple in situ polymerization of 2‐hydroxyethyl methacrylate, dimethylaminoethyl methacrylate and ethylene dimethacrylate, using (S)‐ornidazole ((S)‐ONZ) as template in a binary porogenic mixture consisting of toluene and dodecanol. The composition of the polymerization mixture was systematically altered and optimized by altering the amount of monomers as well as the composition of the porogenic solvent. The column performance was evaluated in pressure‐assisted CEC mode. Separation conditions such as pH, voltage, amount of organic modifier and salt concentration were studied. The optimized monolithic column resulted in excellent separation of a group of structurally related nitroimidazole drugs within 10 min in isocratic elution condition. Column efficiencies of 99 000, 80 000, 103 000, 60 000 and 99 000 plates/m were obtained for metronidazole, secnidazole, ronidazole, tinidazole and dimetridazole, respectively. Parallel experiments were carried out using molecularly imprinted and non‐imprinted capillary columns. The separation might be the result of combined effects including hydrophobic, hydrogen bonding and the imprinting cavities on the (S)‐ONZ‐imprinted monolithic column. 相似文献
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Water-compatible ciprofloxacin-imprinted monolithic columns were synthesized in water-containing systems for selective extraction of ciprofloxacin from human urine samples. Methanol-water (10:3, v/v) was used as a porogenic solvent and the obtained monolithic imprinted polymers reveal high selectivity to ciprofloxacin in an aqueous environment; the affinity can be easily controlled by adjusting the pH of the mobile phase. Owing to the unique porous structure and flow-through channels existing in the network skeleton of the monolithic MIP, urine samples could be directly injected into the column, proteins and other biological matrix were quickly washed out and ciprofloxacin was selectively retained and enriched. Good linearity was obtained from 0.08 to 400 mg/L (r=0.998) with the relative standard deviations less than 3.6%. The limit of detection of the method was 0.04 mg/L and the recoveries were more than 94.5% at three different concentrations. Moreover, by increasing the injection volume to 2.0 mL, the sensitivity of the method could be improved 100-fold according to the peak height of ciprofloxacin. This expedient greatly simplified the overall procedure, resulting in a rapid and efficient sample analysis while maintaining precision and accuracy. 相似文献
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4-氨基吡啶印迹聚合物毛细管整体柱的电色谱识别机理 总被引:4,自引:0,他引:4
在石英毛细管中原位聚合制备了4-氨基吡啶印迹聚合物毛细管整体柱,通过考察流动相中乙腈比例对4-氨基吡啶、2-氨基吡啶和硫脲在分子印迹聚合物毛细管整体柱、空白聚合物毛细管整体柱和硅烷化衍生的开管柱上迁移时间和分离情况的影响,研究了4-氨基吡啶分子印迹聚合物毛细管整体柱的CEC识别机理。发现有机添加剂的含量对印迹聚合物的印迹识别能力影响很大,甚至能改变混合物的流出顺序。根据随乙腈含量改变混合物迁移时间和流出顺序的变化规律,可以推测:随着乙腈含量的提高,色谱保留对迁移的影响越来越大;随着乙腈含量的降低,电泳对迁移的影响越来越大。 相似文献
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Vaz FA de Castro PM Molina C Ribeiro SJ Polachini FC Messaddeq Y Nunes AP de Oliveira MA 《Talanta》2008,76(1):226-229
Photopolymerized sol-gel monolithic columns for use in capillary electrochromatography were prepared in 125 microm i.d. polyacrylate-coated fused-silica capillaries. The polyacrylate-coating, unlike the polyimide one, is transparent to the radiation used (approximately 370 nm), and thus, no coating removal is necessary. This is a very important particularity since intrinsic capillary column characteristics, such as flexibility and mechanical resistance, are unchanged. A mixture containing metacryloxypropyltrimethoxysilane (MPTMS) as the polymeric precursor, hydrochloric acid as the catalyst, toluene as the porogen and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (Irgacure 819) as the photoinitiator was irradiated at 370 nm for 20 min inside the capillaries to prepare the columns through sol-gel approach. The versatility and viability of the use of polyacrilate as a new capillary external coating were shown through preparation of two columns under different conditions, which were tested in electrochromatography for separation of standard mixture containing thiourea (marker compound), propylbenzene, phenanthrene and pyrene. 相似文献