三聚氰胺分子印迹聚合物的制备及奶制品中三聚氰胺的分离

采用分子印迹技术,以三聚氰胺为模板分子,甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,合成了对三聚氰胺具有较好选择性的分子印迹聚合物.通过静态平衡结合实验研究了该聚合物的结合能力和选择性能,与化学组成相同的相应非印迹聚合物相比,三聚氰胺的分子印迹聚合物对三聚氰胺有较高的吸附性能和选择性.以该分子印迹聚合物为固相萃取材料填充固相萃取小柱,可以从奶粉、纯牛奶等奶制品中选择性地分离、富集三聚氰胺,并有效地去除奶制品中的复杂基质,取得了良好的效果.对奶粉和液态奶提取液的加标回收率分别为91% ～103%、93% ～98%,相对标准偏差(n=3)分别为7.9%和1.1%.该分子印迹聚合物还有望用于其它奶制品的分析.     

三聚氰胺磁性印迹固相萃取材料的制备及其应用

采用磁性氧化石墨烯(GO)为载体,三聚氰胺(MEL)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,制备了新型三聚氰胺磁性印迹聚合物。 采用扫描电子显微镜(SEM)、透射电子显微（TEM）、差热分析(TG)和样品振动磁强计(VSM)对该磁性印迹聚合物进行表征和分析,结果表明,在氧化石墨烯表面成功制备磁性印迹聚合物。 结合高效液相色谱分析技术对该印迹聚合物的吸附性能进行检测,结果表明,该磁性印迹聚合物对三聚氰胺表现出特异性吸附性能,最大吸附容量为33.11 mg/g;相对于环丙氨嗪和三聚氰酸,三聚氰胺的选择因子(β)分别是2.43和2.84。 结合磁固相萃取与液相色谱检测技术,实现了牛奶样品溶液中三聚氰胺的分离、富集和检测。     

利用分子印迹技术预处理生物样品中头孢药物的研究

优化了头孢硫脒分子印迹聚合物的合成条件,探讨了分子印迹技术和固相萃取联用对血浆中头孢硫脒的分离富集,发现用4-乙烯基吡啶作功能单体合成的分子印迹聚合物作为固相萃取填充料,能定量吸附血浆中的头孢硫脒,并初步研究了其吸附机理。     

一种高选择性固相萃取吸附剂--分子印迹聚合物

固相萃取是对样品富集、分离的一种有效方法,因而得到广泛应用.分子印迹是近些年发展起来的新技术,由于分子印迹聚合物具有高的选择性,被应用于环境、药物、生物、食品等样品的分析.本文介绍了固相萃取和分子印迹技术的原理以及两者结合用于固相萃取的过程,对近10年来国内外分子印迹聚合物应用于固相萃取的研究工作进行了总结和评述,并对其将来的发展进行了展望.     

分子印迹技术在固相萃取中的应用

对2000-2010年间国内外文献报道的有关分子印迹技术在固相萃取中的应用进行了综述。主要内容包括分子印迹技术和固相萃取技术的原理、分子印迹聚合物的制备和分子印迹-固相萃取的两种操作模式,着重介绍了分子印迹-固相萃取在环境、食品、生物医药等领域中的应用(引用文献32篇)。     

分子印迹固相萃取-气相色谱-质谱法测定猪尿中4种β-受体激动剂

建立了分子印迹固相萃取结合气相色谱-质谱测定猪尿中β-受体激动剂氯丙那林、马步特罗、克伦特罗、莱克多巴胺的方法.应用分子印迹柱富集并净化猪尿液中4种β-受体激动剂,比较了分子印迹固相萃取与常规固相萃取的净化效果.通过BSTFA-1％ TMS硅烷化衍生,氘代克伦特罗和氘代莱克多巴胺为校正内标,气相色谱-质谱测定.在优化条...     

分子印迹固相萃取牛奶中甲胺磷

以甲胺磷为印迹分子、α-甲基丙烯酸为功能单体及三羟甲基丙烷三丙烯酸酯为交联剂,通过悬浮聚合法制备甲胺磷分子印迹聚合物(MIP)微球,并用该聚合物进行了牛奶中甲胺磷残留的固相萃取研究.静态吸附实验表明,在结构相似物乙酰甲胺磷和水胺硫磷为竞争底物存在下,MIP对甲胺磷有良好的吸附识别能力.在优化条件下,印迹分子的固相萃取回收率达96.4%,能够用于甲胺磷的富集,而空白聚合物却不具备这样的特性.当实际牛奶样品中甲胺磷、乙酰甲胺磷和水胺硫磷加标水平为100μg/kg时,甲胺磷回收率达87.4%,乙酰甲胺磷和水胺硫磷的回收率低于15%.结果表明分子印迹固相萃取对甲胺磷有很好的专一选择性,且回收率能够满足农药残留分析要求.在相同实验条件下,与C18固相萃取柱进行比较,分子印迹固相萃取的选择性及样品净化能力优势明显.     

分子印迹聚合物固相萃取研究进展

对最新报道的分子印迹聚合物作为固相萃取剂及其在色谱样品前处理方面的应用进行综述和展望,主要包括固相萃取、基质固相分散萃取、固相微萃取、搅拌棒吸附萃取和磁性材料萃取,同时总结了分子印迹聚合物制备技术面临的挑战和问题,提出了可能的解决方案。     

样品中分子印迹固相萃取技术的最新应用进展

现代样品体系一般复杂,采用一般的分析方法对其分离富集难度较大。分子印迹聚合物的高选择性使其在复杂体系样品的净化富集中具有很强的应用潜力,本文对分子印迹聚合物作为固相萃取剂及其在色谱样品前处理方面的应用进行了综述和展望,主要包括分子印迹中空纤维萃取、分子印迹固相萃取柱萃取、分子印迹整体柱萃取、分子印迹膜萃取、搅拌棒吸附萃取、磁性材料萃取等技术,同时总结了分子印迹固相萃取技术在食品分析、环境分析以及药物与生物分析等方面的应用进展。     

虚拟分子印迹固相萃取技术检测食品中10种三嗪类除草剂残留

以正丁基三聚氰胺为虚拟模板,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,采用悬浮聚合法制备得到对三嗪类除草剂具有高选择性的分子印迹聚合物。运用分子模拟技术探讨了虚拟模板的筛选方法;利用高效液相色谱法考察了印迹聚合物对三嗪类除草剂的选择吸附性;以此聚合物作为固相萃取填料,研究了分离、富集食品中三嗪类除草剂的最佳萃取条件。与其它固相萃取柱相比,所制备的分子印迹固相萃取柱对三嗪类除草剂有较好的分子识别能力,能有效降低基质效应。基质加标三嗪类除草剂回收率为87.8%～105.2%;相对标准偏差(RSD)均小于13%(n=6)。     

Comparison of multi-recognition molecularly imprinted polymers for recognition of melamine,cyromazine, triamterene,and trimethoprim

Three fragmental templates, including 2,4-diamino-6-methyl-1,3,5-triazine (DMT), cyromazine (CYR), and trimethoprim (TME), were used to prepare the fragment molecularly imprinted polymers (FMIPs), respectively, in polar ternary porogen which was composed of ionic liquid ([BMIM]BF₄), methanol, and water. The morphology, specific surface areas, and selectivity of the obtained FMIPs for fragmental analogues were systematically characterized. The experimental results showed that the FMIPs possessed the best specific recognition ability to the relative template and the greatest imprinting factor (IF) was 5.25, 6.69, and 7.11 of DMT on DMT-MIPs, CYR on CYR-MIPs, and TME on TME-MIPs, respectively. In addition, DMT-MIPs also showed excellent recognition capability for fragmental analogues including CYR, melamine (MEL), triamterene (TAT), and TME, and the IFs were 2.08, 3.89, 2.18, and 2.60, respectively. The effects of pH and temperature on the retention of the fragmental and structural analogues were studied in detail. Van’t Hoff analysis indicated that the retention and selectivity on FMIPs were an entropy-driven process, i.e., steric interaction. The resulting DMT-MIPs were used as a solid-phase extraction material to enrich CYR, MEL, TAT, and TME in different bio-matrix samples for high-performance liquid chromatography analysis. The developed method had acceptable recoveries (86.8–98.6 %, n?=?3) and precision (2.7–4.6 %) at three spiked levels (0.05–0.5 μg g^?1).     

Novel molecularly imprinted polymers based on multiwalled carbon nanotubes with bifunctional monomers for solid-phase extraction of rhein from the root of kiwi fruit

A novel molecularly imprinted polymers based on multiwalled carbon nanotubes synthesized by precipitate polymerization was applied as a selective sorbent for separation and determination of rhein (4,5-dihydroxyanthraquinone-2-carboxylic acid) from the root of kiwi fruit samples coupled with high performance liquid chromatography (HPLC). The molecularly imprinted polymers were prepared with methacrylic acid and 4-vinylpyridine as bifunctional monomers. The chemical structure of the molecularly imprinted polymers was characterized by Fourier transform infrared spectrometer. The equilibrium rebinding experiment and competitive adsorption experiment showed that these imprinted polymers exhibited good adsorption ability toward rhein. The Langmuir adsorption equilibrium constant, K(m) , and theoretical maximum adsorption capacity, Q(m) , were estimated to be 0.43 and 6.77 mg g(-1) , respectively. Compared with molecularly imprinted polymers prepared with methacrylic acid or 4-vinylpyridine solely, the molecularly imprinted polymers synthesized with bifunctional monomers showed enhanced molecular imprinting effect and higher adsorption capacity for the template rhein. The performances of the molecularly imprinted polymers utilized as solid phase extraction sorbent were investigated in detail. The molecularly imprinted polymers prepared by the method proposed in this work could successfully apply to extraction and determination of rhein from the root of kiwi fruit samples coupled with HPLC.     

基于多齿功能单体的三聚氰胺印迹材料的制备及应用

以三聚氰胺(MEL)为模板分子,采用沉淀聚合方法研究了以衣康酸(IA)为多齿功能单体,乙二醇二甲基丙烯酸酯(EGDMA)为交联剂时,组分之间摩尔比对三聚氰胺印迹聚合物(MIP)选择性的影响.研究发现,当MEL与IA摩尔比为1∶1.5时,所合成的MIP对三聚氰胺具有最佳选择性,选择性系数k=10.41(以三聚氰酸为对照物).此时IA的识别位点(羧基)与三聚氰胺的可识别位点(胺基)摩尔比为1∶1,因此,不会出现由过量功能单体引起的非特异性吸附.Scatchard分析结果表明,这种MIP能够在更宽的三聚氰胺浓度范围(1～100 mg/L)内只表现出特异性吸附.以灭蝇胺为对照物时,kNIP<1但kMIP>1,该结果证明MIP对分子的形状有良好的识别能力.最后,以制备的MIP为固相萃取吸附剂,结合高效液相色谱/紫外检测器(HPLC/UV)建立了三聚氰胺测定方法.当牛奶(奶粉)中MEL的加标浓度分别为15,600和4500μg/L(μg/kg)时检测的加标回收率为92.34%～109.4%.     

Innovative method for the enrichment of high‐polarity bioactive molecules present at low concentrations in complex matrices

Ginsenoside Rg1 is a valuable bioactive molecule but its high polarity and low concentration in complex mixtures makes it a challenge to separate Ginsenoside Rg1 from other saponins with similar structures, resulting in low extraction efficiency. The successful development of effective Rg1 molecularly imprinted polymers that exhibit high selectivity and adsorption may offer an improved method for the enrichment of active compounds. In this work, molecularly imprinted polymers were prepared with two different methods, precipitation polymerization or surface imprinted polymerization. Comparison of the adsorption abilities showed higher adsorption of the surface molecularly imprinted polymers prepared by surface imprinted polymerization, 46.80 mg/g, compared to the 27.74 mg/g observed for the molecularly imprinted polymers prepared by precipitation polymerization. Therefore, for higher adsorption of the highly polar Rg1, surface imprinted polymerization is a superior technique to make Rg1 molecularly imprinted polymers. The prepared surface molecularly imprinted polymers were tested as a solid‐phase extraction column to directionally enrich Rg1 and its analogues from ginseng tea and total ginseng extracts. The column with surface molecularly imprinted polymers showed higher enrichment efficiency and better selectivity than a C₁₈ solid‐phase extraction column. Overall, a new, innovative method was developed to efficiently enrich high‐polarity bioactive molecules present at low concentrations in complex matrices.     

Facile preparation of polydopamine‐coated imprinted polymers on the surface of SiO2 for estrone capture in milk samples

Estrone molecularly imprinted polymers were synthesized through the self‐polymerization of dopamine on the surface of silica gels, which had the characteristics of mild polymerization conditions, simple reaction procedure and good specific recognition ability for estrone. The estrone molecularly imprinted polymers were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, elemental analysis and nitrogen adsorption–desorption tests. The characterization confirmed that the imprinted polymers were successfully grafted on the surface of silica gels. Through investigating the adsorption performance, the prepared estrone molecularly imprinted polymers exhibited high adsorption capacity, fast mass transfer, as well as excellent selectivity toward estrone. The estrone molecularly imprinted polymers as the solid‐phase extraction adsorbent coupled with high‐performance liquid chromatography was developed to determine estrone from the milk samples. The developed estrone molecularly imprinted polymer solid‐phase extraction with high‐performance liquid chromatography method exhibited satisfactory specificity, precision, accuracy and good linearity relationship in the range of 0.2–20 μg/mL. The developed method is simple, fast, effective and high specificity method and it provides a new method to detect the residues of estrone in animal foods.     

Selective Preconcentration of Mezlocillin from Eggs by Molecularly Imprinted Polymers on Silica

Surface molecularly imprinted polymers for mezlocillin were used for the selective solid-phase extraction of mezlocillin from eggs. The molecularly imprinted polymers were prepared using mezlocillin as the template, methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as the cross-linker, silica particle as the support and were characterized by infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. The adsorption properties of polymers were investigated in detail. The obtained polymers provided high imprinting efficiency to mezlocillin with an imprinting factor of 3.72 and were used as selective sorbents for mezlocillin. Molecularly imprinted solid-phase extraction followed by high-performance liquid chromatography was used for the determination of mezlocillin in eggs and the conditions were evaluated. The average recovery of mezlocillin in fortified eggs was between 69.8 and 82.3% with a relative standard deviation less than 6.9%. The results demonstrate the application of molecularly imprinted polymers for the extraction of mezlocillin from biological samples.     

Preparation of a stoichiometric molecularly imprinted polymer for auramine O and application in solid‐phase extraction

We describe a stoichiometric approach to the synthesis of molecularly imprinted polymers specific for auramine O. Using the stoichiometric interaction in molecular imprinting, no excess of binding sites is necessary and binding sites are only located inside the imprinted cavities. The free base of the template was obtained to facilitate the interaction with the monomers. Itaconic acid was selected as the functional monomer, and stoichiometric ratio of the interaction with the free base was investigated. The molecularly imprinted polymer preparation conditions such as cross‐linker, molar ratio, porogen were optimized as divinylbenzene, 1:2:20 and chloroform/N,N‐dimethylformamide, respectively. Under the optimum conditions, a good imprinting effect and very high selectivity were achieved. A solid‐phase extraction method was developed using the molecularly imprinted polymers as a sorbent and extraction procedure was optimized. The solid‐phase extraction method showed a high extraction recovery for auramine O in its hydrochloride form and free form compared to its analogues. The results strongly indicated that stoichiometric imprinting is an efficient method for development of high selectivity molecularly imprinted polymers for auramine O.     

Hybrid molecularly imprinted polymers modified by deep eutectic solvents and ionic liquids with three templates for the rapid simultaneous purification of rutin,scoparone, and quercetin from Herba Artemisiae Scopariae

Different kinds of deep eutectic solvents based on choline chloride and ionic liquids based on 1‐methylimidazole were used to modify hybrid molecularly imprinted polymers with the monomer γ‐aminopropyltriethoxysilane‐methacrylic and three templates (rutin, scoparone, and quercetin). The materials were adopted as solid‐phase extraction packing agents, and were characterized by FTIR spectroscopy and field emission scanning electron microscopy. The hybrid molecularly imprinted polymers modified by deep eutectic solvents had high recoveries and a strong recognition of rutin, scoparone, and quercetin in Herba Artemisiae Scopariae than those modified by ionic liquids. In the procedure of solid‐phase extraction, deep eutectic solvents‐2‐hybrid molecularly imprinted polymers were obtained with the best recoveries with rutin (92.27%), scoparone (87.51%), and quercetin (80.02%), and the actual extraction yields of rutin (5.6 mg/g), scoparone (2.3 mg/g), and quercetin (3.4 mg/g). Overall, the proposed approach with the high affinity of hybrid molecularly imprinted polymers might offer a novel method for the purification of complex samples.