Surface molecularly imprinted polymers based ZnO quantum dots as fluorescence sensors for detection of diethylhexyl phthalate with high sensitivity and selectivity

This work describes the preparation of molecularly imprinted polymers using ZnO quantum dots, which were used for the selective detection of diethylhexyl phthalate (DEHP). Methacrylic acid, ethylene glycol dimethacrylate, 2,2′‐azobis(2‐methylpropionitrile) and ZnO were used as functional monomer, crosslinker, initiator and optical material, respectively. Molecularly imprinted polymers were successfully synthesized, and the linear relationship between fluorescence intensity and amount was from 0.5 to 40 µmol L^?1 for DEHP. The coefficient of correlation was 0.9923 and the imprinting factor was 11.16. The results were above 97.50% and relative standard deviation below 3.86% for the detection of DEPH in actual water samples. This study could provide a novel method using molecularly imprinted polymers for highly selective and sensitive detection of DEHP. © 2018 Society of Chemical Industry     

沉淀聚合法制备咖啡因分子印迹聚合物微球

以咖啡因为印迹分子,甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,偶氮二异丁腈为引发剂,采用沉淀聚合法在乙腈溶液中制备了针对咖啡因的分子印迹聚合物微球。对沉淀聚合中单体、引发剂、溶剂用量的比例关系进行探索,并利用平衡结合实验研究了聚合物对印迹分子的吸附性能,结果表明该印迹聚合物微球呈现出较好的结合能力。     

Morphologies and binding characteristics of molecularly imprinted polymers prepared by precipitation polymerization

Molecularly imprinted polymers using L ‐2‐chloromandelic acid as templates were prepared by precipitation polymerization. The polymer particles exhibited a regular shape in the nanoscale range; moreover, the size and the uniformity of the particles were influenced by the concentration of monomers, polymerization temperature, types and concentrations of initiators. The experimental binding tests indicated that the nanospherical imprinted polymers possessed higher specific affinity to templates in comparison with traditional imprinted polymers prepared by bulk polymerization. Two classes of specific binding sites in the polymer matrix were investigated by the Scatchard method and ‘Hyperchem’ simulation studies. Copyright © 2003 Society of Chemical Industry     

Preparation and characterization of monodisperse molecularly imprinted polymer microspheres by precipitation polymerization for kaempferol

A new kind of molecularly imprinted polymer (MIP) microspheres for the selective extraction of kaempferol was prepared by precipitation polymerization using 4-vinylpridine (4-VP) and ethylene glycol dimethacrylate (EDMA) as functional monomer and cross-linker respectively. The synthesis conditions, such as ratios of 4-VP/EDMA and polymerization time were discussed in detail. Results showed that the 2% was the optimal concentration of co-monomers to obtain monodisperse MIP microspheres, the best ratio of 4-VP/EDMA was 1:2, and 24 h was considered as the proper polymerization time. Compared with the MIP agglomeration or coagulum particles, monodisperse MIP microspheres showed the better adsorption capacity: the saturated adsorption capacity of monodisperse MIP microspheres was 7.47 mg g^?1, the adsorption equilibrium could be obtained in 30 min. Finally, the adsorption performances of the optimal MIP microspheres were evaluated by kinetic adsorption, adsorption isotherm, and selective adsorption experiments, which indicated that the adsorption mechanism were chemical single layer adsorption and the separation factor was up to 3.91 by comparing with the structure similar compound (quercetin). The MIP microspheres exhibit prospects in the kaempferol efficient and selective separation.     

分子印迹电化学传感器检测链霉素

为实现链霉素的快速、灵敏测定,将特异性强的分子印迹技术与检测灵敏度高的电化学检测方法结合,构建链霉素分子印迹电化学传感器。以链霉素为模板分子,吡咯为功能单体,利用电化学聚合方法制备分子印迹聚合物(MIP)膜。在最优化实验条件下,以铁氰化钾为探针,利用循环伏安法(CV)对链霉素进行定量测定及传感器性能研究。结果表明:传感器线性范围为5.00×10~(-8)～8.00×10~(-5)mol/L,最低检出限(LOD)为3.45×10~(-8)mol/L,为链霉素的测定提供了高效的方法。     

Synthesis of highly selective spherical caffeine imprinted polymers via ultrasound‐assisted precipitation polymerization

A facile and efficient method for synthesis of molecularly imprinted polymers via ultrasound‐assisted precipitation polymerization was developed. Caffeine was applied as a model template in the imprinting using methacrylic acid and ethylene glycol dimethacrylate as a functional monomer and a crosslinker, respectively. Polymerization under sonochemical conditions proceeded rapidly (within 3 h at 60°C) to afford polymer microspheres with narrow size distributions in excellent yields while maintaining the binding specificity toward the template. It was found that the imprinted polymer prepared at low initial temperature (40°C) exhibited the best caffeine binding performance in terms of specificity and selectivity. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Precipitation polymerization of molecularly imprinted polymers for recognition of melamine molecule

Molecular imprinted polymer microspheres (MIPs) were prepared by precipitation polymerization using melamine as template molecule, methacrylic acid (MAA) as functional monomer, trimethylol‐propane trimethacrylate (TRIM) as crosslinking agent, acetonitrile as solvent and dispersion medium. Release of the template was performed by continuous extraction with methanol containing 10% acetic acid. The microspheres were observed by scanning electron microscopy (SEM). The perfect microspheres were produced when the addition of crosslinker was 7.48 mmol. The binding capacity of MIPs was examined, Q_max = 68.36 μmol g^?1, and the dissociation constant at binding site of MIPs, K_d = 0.761, was estimated. Compared with the performance of conventional imprinted polymer, the imprinted microspheres showed high selectivity in special binding to template molecule. The imprinted microspheres could be used as the stationary phase in HPLC or SPE for selective extraction of melamine in daily products. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation and characterization of molecularly imprinted polymer of bovine serum albumin

Molecularly imprinted polymer beads of bovine serum albumin (BSA) were prepared via inverse phase suspension polymerization, using BSA as the template molecule, a combination of acrylamide and methacrylic acid (MAA) as double functional monomers, and N, N′‐methylene bisacrylamide as the crosslinker. The effect of different monomer ratios and degrees of crosslinking were investigated. When both selectivity and physical properties of the resultant polymer beads were taken into account, the ratio of MAA in the total monomers was chosen at 40% (m/m) and the degree of crosslinking at 30% (n/n), the resultant polymer beads had good selectivity (α = 2.77) and good physical properties. The effects of pH and temperature were studied. It turned out that the functionalization of polymers of BSA prepared via inverse‐phase suspension polymerization exhibited specific recognition for BSA. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Extraction and determination of malachite green from aquatic products based on molecularly imprinted polymers

Molecularly imprinted polymers (MIPs) were synthesized using malachite green (MG) as template, and methacrylic acid/sodium methacrylate as composite monomers. The equilibrium dissociation constant and apparent maximum adsorption capacity of the MIPs reach 12.2 mg·L^?1 and 3.2 mg·g^?1, respectively. The MIPs demonstrate excellent recognition ability due to high-affinity sites constructed by the electrostatic interaction and hydrogen bonds between template and composite monomers. The MIPs were successfully employed for the detection of MG residue in aquatic products coupled with high-performance liquid chromatography (HPLC) with a detection limit of 0.57 μg·kg^?1.     

Surface molecularly imprinted polymer microspheres based on nano‐TiO2 for selective recognition of kaempferol

The molecular imprinting technique is a new method for preparing molecularly imprinted polymers (MIPs) with specific molecular recognition sites for certain target molecules. In this study, a novel, facile preparation method was presented, called “seed precipitation polymerization,” for the synthesis of MIPs via surface imprinting and a support matrix. In the polymerization process, kaempferol was used as the template molecule, methacrylic acid as the functional monomer, nano‐TiO₂ as the support, azodiisobutyronitrile as the initiator, and ethylene glycol dimethacrylate as the crosslinker in acetonitrile solvent. The synthesized T‐MIP and MIP were analyzed by infrared spectroscopy and scanning electron microscopy. In addition, the obtained polymers were evaluated by adsorption isotherms and dynamic curves for their selective recognition properties for kaempferol. The results show that T‐MIP shows regular spherical particles; the adsorption dynamic curves of T‐MIP show that the adsorption capacity increases with time and reaches a maximum value and then finally reaches equilibrium, and the T‐MIP exhibits a higher affinity for kaempferol than does the MIP. The adsorption follows pseudo‐second‐order kinetics, the Freundlich adsorption equation fits the experimental data well, and there is strong evidence for multiple‐layer adsorption. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44888.     

磁性分子印迹聚合物的制备与应用研究

磁性分子印迹聚合物是在磁性微粒表面利用分子印迹技术合成具有超顺磁性、高选择性、高吸附性和特异性识别的聚合物。能在外加磁场作用下实现快速分离和定向移动,是一种新型高分子材料。本文主要介绍了物理法、化学法和模板法3种磁性微粒的制备方法,以及利用分子印迹技术制备磁性分子印迹聚合物,并探讨了悬浮聚合、乳液聚合和沉淀聚合3种聚合方法的研究进展,总结了磁性分子印迹聚合物在农药残留、兽药残留、重金属残留和生物医学方面的应用。分析表明磁性分子印迹聚合物在生物医学领域,尤其是抗菌治疗方面有良好的发展前景。     

Clozapine recognition via molecularly imprinted polymers; bulk polymerization versus precipitation method

Two clozapine (CLZ) imprinted polymers were prepared by bulk and precipitation methods. Methacrylic acid and ethylene glycol dimethacrylate (EDMA) were used as functional and crosslinker monomers, respectively. The mean diameter and particle size distribution of the imprinted (P‐MIP) and nonimprinted (P‐NIP) particles obtained in precipitation method were examined. A conventional batch‐adsorption test was applied for characterization of CLZ–polymer interaction. Dissociation constant (K_D) and maximum binding sites (B_max) were calculated using Scatchard analysis. To evaluate the recognition properties of polymers, phenytoin (PTN) binding to each polymer was also studied and compared to CLZ. The imprinting factor (IF) and selectivity factor (α) were also determined for each polymer. Average diameter and polydispersity of P‐MIP were 925 nm and 0.17, respectively. The data for P‐NIP were 1.05 μm and 0.18. The K_D, IF, and α values calculated for P‐MIP were 0.45 μM, 3.26, and 17.43, respectively. The data for imprinted polymer, prepared by bulk polymerization (B‐MIP), were 14.5 μM, 1.95, and 3.67. These results demonstrated that precipitation polymerization is a more convenient, more effective, and more reproducible method than bulk polymerization for the synthesis of uniformly sized micron and submicron‐imprinted polymer particles. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

焦性没食子酸分子印迹聚合物的制备与吸附特征研究

以焦性没食子酸为模板分子,丙烯酸为功能单体,甲醇为溶剂,研究了模板分子与功能单体的结合比例,表明焦性没食子酸和丙烯酸之间通过氢键形成1∶1型配合物。在模板分子与功能单体、交联剂物质的量的比为1∶4∶20的条件下,采用沉淀聚合法制备了焦性没食子酸分子印迹聚合物微球。静态吸附实验表明,可制备出吸附量大且特异性识别能力较高的分子印迹聚合物,对焦性没食子酸有较高的亲和性和选择性。采用恒温振荡平衡吸附法以及Scatchard分析研究了聚合物的吸附特征,结果表明焦性没食子酸分子印迹聚合物在水环境下存在2种吸附位点,最大表观吸附量分别为7.5516μg/mg和11.9225μg/mg,平衡离解常数分别为9.2720×10-3mmol/L和0.1892 mmol/L。     

Preparation of molecularly imprinted polymer microspheres via reversible addition-fragmentation chain transfer precipitation polymerization

The first combined use of reversible addition-fragmentation chain transfer (RAFT) polymerization and precipitation polymerization in the molecular imprinting field is described. The new polymerization technique, namely RAFT precipitation polymerization (RAFTPP), provides MIP microspheres with obvious molecular imprinting effects towards the template, fast template binding process and an appreciable selectivity over structurally related compounds, while only irregular MIP aggregates were obtained via traditional radical precipitation polymerization (TRPP) under similar reaction conditions. The MIP microspheres prepared via RAFTPP have proven to show improved binding capacity, larger binding constant and apparent maximum number for high-affinity sites, and significantly higher high-affinity binding site density in comparison with the MIP prepared via TRPP.     

热聚合制备左旋氧氟沙星分子印迹聚合物的条件

以左旋氧氟沙星(LVFX)为模板,以α-甲基丙烯酸(MAA)为功能单体,乙二醇二甲基丙烯酸酯(EDMA)为交联剂,采用热聚合方式,通过条件优化获得了对左氧氟沙星有特异选择性吸附的分子印迹聚合物(M IPs)。最优化条件为n(LVFX)∶n(MAA)∶n(EDMA)=1∶4∶15,聚合温度60℃,聚合时间48 h,溶剂氯仿,用量10 mL。通过结合实验分析,在最优化条件下制得的M IPs对左氧氟沙星具有很好选择性和吸附能力,分离因子α(LVFX/OLFX)为1.56。     

沉淀聚合法制备烟酰胺分子印迹聚合物微球

以烟酰胺为模板分子,甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,偶氮二异丁腈为引发剂,乙腈为溶剂,采用沉淀聚合法制备了烟酰胺分子印迹聚合物,通过静态平衡吸附和色谱分析对印迹聚合物进行表征,结果表明,印迹聚合物对烟酰胺分子具有很好的吸附能力和特异识别性。     

三唑酮分子印迹纳米球的制备及应用

建立了烟叶中8种三唑类杀菌剂残留的分子印迹固相萃取-超高效液相色谱-串联质谱（MISPE-UPLC-MS/MS）检测方法。实验中,运用计算机模拟技术筛选最佳功能单体及溶剂,并确定最优聚合反应配比,估算了TDF-MAA的自组装过程与红外光谱图,热力学分析表明TDF-MAA自组装为吸热非自发过程,预聚合反应温度拟定为30℃;采用沉淀聚合法制备了三唑酮分子印迹聚合物纳米颗粒,颗粒粒径分布均匀,平均粒径为200nm;该纳米颗粒对模板分子及其结构类似物具有良好的特异性吸附能力,针对模板分子的分离印迹因子达到2.42;将加标烟叶样品经该纳米颗粒组装的固相萃取柱进行前处理,用UPLC-MS/MS分析前处理液,烟叶中8种三唑类杀菌剂的固相萃取回收率为70.14%～105.43%,检出限为4.82～11.97ng/mL,相对标准偏差（RSD）为0.26%～2.27% （n=6）,实现了复杂基质烟叶中多种三唑类杀菌剂的同时检测。     

Synthesis and optimization of molecularly imprinted polymers for quercetin

Molecularly imprinted polymers (MIPs) were synthesized through solution polymerization using quercetin as the template molecule, N‐vinylpyrrolidone and acrylic acid as functional monomers, N,N′‐methylenebiacrylamide as crosslinker and the redox system L ‐ascorbic acid and hydrogen peroxide as initiator in the porogen of ethanol and water. During the optimization process an interference compound, genistein (5,7,4′‐trihydroxy isoflavone), which possesses the same skeleton and functional groups as quercetin, was adopted to optimize the preparation conditions, and the separation degree of the MIP to quercetin and genistein was chosen to optimize each factor. The synthesized MIP under optimal conditions showed a specific recognition of quercetin from a mixture of quercetin and genistein. Thereafter, the structure of the MIP was comparatively characterized by Fourier transform infrared spectroscopy, scanning electron microscopy and Brunauer–Emmett–Teller analysis using non‐imprinted molecular polymers as control. In addition, the kinetics of the adsorption process were also studied, and Scatchard analysis revealed that heterogeneous binding sites were formed in the polymers. Copyright © 2012 Society of Chemical Industry     

基于氮掺杂碳量子点的荧光微球制备和Fe3+检测

分别以尿素、氨水、二乙烯三胺、多乙烯多胺为氮源,绿色廉价的白菜为碳源,采用水热法合成氮掺杂的蓝色荧光碳量子点,结果表明多乙烯多胺氮掺杂碳量子点（NCDs）荧光量子产率最高为53.3%。然后将NCDs作为荧光探针应用于荧光微球制备和Fe³⁺检测方面,以三聚氰胺甲醛（MF）为载体,合成了氨基化MF荧光微球;基于Fe³⁺对NCDs良好的荧光猝灭效应,建立了一种荧光测定Fe³⁺的方法,并对NCDs和MF荧光微球的结构和性能进行表征。结果表明,NCDs的荧光性能得到了显著的改善;MF荧光微球单分散性好、荧光性能好且稳定,在生物医学领域方面有重要的应用价值;NCDs对Fe³⁺具有单一选择性,Fe³⁺浓度在0~2μmol/L内与NCDs的荧光猝灭程度呈良好的线性关系（R²=0.9945）,检出限为0.035μmol/L。将该体系应用于实际水样中Fe³⁺的测定,相对标准偏差（RSD,n=6）在1.42%~3.02%内,加标回收率在98.7%~104.5%之间。该体系对Fe³⁺检测灵敏性好、选择性高以及抗干扰性强,在离子分析检测方面有潜在的应用前景。     

Synthesis of molecularly imprinted microspheres for recognition of trans‐aconitic acid

In the presence of a template molecule, trans‐aconitic acid and, using acetonitrile as solvent and dispersing medium, monodispersed microspheres with a diameter of 600–700 nm bearing molecularly imprinted binding sites were prepared by precipitation polymerization. It was found that the concentrations of template, monomer, and crosslinking agent as well as the chemical structure of the template greatly affect the polymer configuration. Microspheres are produced only when the concentration of the template molecule and the functional monomer are finely tuned. Comparison with the performance of a conventional imprinted polymer monolith showed that the imprinted microsphere had obvious advantages in specific binding to template molecule. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 542–547, 2004