分子印迹填充色谱柱用于药物分离的研究进展

分子印迹聚合物(MIP)是由模板分子与功能单体相互作用,然后在合适的条件下加入交联剂聚合而成的一种高分子材料.将该聚合物装填高效液相色谱(HPLC)固定相,可利用其印迹空穴中的特异性识别位点,实现模板分子和竞争分子间的分离.综述了近年来分子印迹填充色谱柱的发展状况、合成方法与袁征手段.重点论述对分子印迹填充色谱柱分离效果和印迹效果产生影响的重要因素,指出模板分子的选择、填料的表面结构以及色谱条件对分离有较大影响.最后,对分子印迹色谱柱在药物分离领域的发展前景进行展望,提出了不足之处.     

表面印迹聚合物的制备及其在药物分离分析中的应用

表面分子印迹技术是在载体表面上发生聚合反应,将分子识别位点建立在载体的外层或者表面。从而使表面分子印迹聚合物具有结合速度快、识别选择性强、结合容量高、提高印迹材料的效率等优点。近年来表面分子印迹技术在药物分离分析中的应用引起人们的关注。简要介绍了表面分子印迹聚合物的原理及4种制备方法(溶胶-凝胶法、接枝共聚法、牺牲载体法、聚合加膜法、活性可控自由基聚合法),并对其在药物分离分析的4个方面(中药提取分离中;药物传感器方面;手性药物拆分中;药物释放中)的应用进行了综述。     

魔芋葡甘聚糖分子量的GPC-LS-RI与LS法研究比较

运用静态激光光散射仪,比较了凝胶渗透色谱-激光光散射联机(GPC-LS-RI)法与(LS)单机法研究魔芋葡甘聚糖(KGM)的重均分子量(-Mw)。实验结果显示,联机法测得KGM的-Mw=2.476×105g/mol,单机法测得KGM的-Mw=2.508×105g/mol,二者差比仅为1.3%,表明两种方法测定KGM重均分子量的实验数值十分接近;同时联机法分析了KGM的多分散系数(-Mw/-Mn)及构象指数(β),而单机法求得了联机法无法测得的KGM分子与溶剂分子之间相互作用的第二维利系数(A2)。这些均为KGM分子形态的理论研究提供了参考依据。     

香椿老叶中黄酮类和皂苷类物质的分离鉴定

目的对香椿老叶中的黄酮类和皂苷类活性物质进行分离鉴定,为进一步开发香椿老叶产品提供理论基础。方法使用柱色谱和高效液相色谱(High Performance Liquid Chromatography, HPLC)对香椿老叶中的物质进行分离纯化,并采用核磁共振(Nuclear Magnetic Resonance, NMR)和红外光谱(Infrared Spectroscopy,IR)对分离物质进行测定。结果香椿老叶中含有芦丁、表儿茶素、槲皮素、异槲皮素、番石榴苷等。利用显色反应初步定性鉴定出香椿皂苷中包括甾体皂苷和三萜皂苷。结论香椿老叶中含有丰富的黄酮类和皂苷类物质,具有广阔的开发前景。     

硒的总量及形态分析综述

综述了近年来硒总量及形态分析研究领域所取得的进展,主要包括:样品前处理技术、形态分离技术中液相色谱分离、毛细管电泳分离、气相色谱分离的优缺点;硒总量分析中氢化物发生原子吸收光谱(HG-AAS)、石墨炉原子吸收光谱法(GF-AAS)、紫外及可见分光光度法、荧光法、电化学法、中子活化技术等的优缺点和各种硒形态检测中HPLC-ICP-MS及ICP-MS的研究现状,同时展望了硒的形态分析技术.     

活性艳蓝KN-R分子印迹CA/PVDF共混膜的制备及性能表征

采用湿相转化法制备了以活性艳蓝KN-R为印迹分子的醋酸纤维素(CA)-聚偏二氟乙烯(PVDF)分子印迹膜(MIM).实验结果表明在一定的制备条件下可制得具有较大吸附结合率的MIM,此时的铸膜液组成为:活性艳蓝KN-R质量浓度硼ω1为0.1%,共混组成比ω(CA):ω(PVDF)=9.5:0.5,聚合物质量浓度ωp,为14%,添加剂LiCl质量浓度ωa为7.5%.所制得的MIM是一种特异分子吸附膜,对印迹分子具有亲和性,其分离机理属于延迟渗透机理.在一定范围(0～0.1%)内,随着印迹分子活性艳蓝KN-R质量浓度增大,MIM的吸附选择性提高.由吸附焓△H0及MIM与印迹分子间结合力强弱的测定结果可知,MIM与印迹分子之间的结合作用力以疏水/范德华力与氢键作用为主.     

水浮莲叶挥发性化学成分的GC/MS法分析

采用气相色谱-质谱联用方法(GC/MS)分析了水浮莲叶中挥发性化学成分。以水蒸气蒸馏法从水浮莲叶中提取挥发油,以毛细管柱为分离柱,在最佳分析条件下共分离出30个化合物,用归一化法测定其相对含量,并用气相色谱-质谱法对分离出的化学成分进行鉴定,共鉴定了26个成分,占挥发油总成分的95·20%。该法对挥发油化学成分的分离效果满意。     

孔道修饰MOF-808混合基质膜制备及其CO_2分离性能

利用MOF-808结构中含有易于被取代的甲酸这一特性,选用一种结构中含有丰富含氮基团的羧酸分子,L-组氨酸,对微波法合成的MOF-808纳米颗粒进行了后合成改性修饰,在其孔道中引入了对CO_2具有较高亲和力的含氮官能团.进一步采用孔道修饰后的MOF-808(MOF-808-His)与聚酰亚胺(6FDA-DAM)复合制备了一种新型混合基质膜,结合气体分离性能测试与膜的微观结构表征系统地分析了孔道修饰对MOF-808/6FDA-DAM混合基质膜CO_2分离性能的影响.结果表明,MOF-808孔道内含氮官能团的引入能够明显改善其对CO_2的选择性吸附能力,进而提高混合基质膜的CO_2/CH_4分离性能.当MOF-808-His质量分数为10%时,混合基质膜的CO_2渗透通量为764 Barrer, CO_2/CH_4分离因子为32.4,比纯6FDA-DAM膜分别提高了104%和35%,超过了CO_2/CH_4分离的Robeson上限.     

活性自由基聚合的白藜芦醇分子印迹聚合物的合成及在葡萄皮白藜芦醇分析中的应用

RAFT试剂介入制备白藜芦醇分子印迹聚合物并用于实际样品中白藜芦醇的分离富集。以二苄基三硫代碳酸酯(DBTTC)为RAFT试剂,以白藜芦醇为印迹化合物,以丙烯酰胺作为功能单体,利用可逆加成-断裂链转移自由基聚合法(RAFT)制备了白藜芦醇分子印迹聚合物。利用扫描电镜、红外光谱和色谱法考察了单体与交联剂比例、引发剂用量、溶剂用量、反应时间和反应温度对印迹聚合物形态结构、印迹聚合物的识别能力及分离效率的影响。结果显示,利用RAFT聚合法制备的白藜芦醇分子印迹聚合物对模板分子的结合量Q达到1 283μg/g,并具有特异性识别作用。通过活性自由基聚合法合成的分子印迹聚合物具有更好的形态结构,对目标分子具有较高的吸附效率。     

水相中色氨酸分子印迹聚合物微球的合成、表征及其识别性能研究

分别以色氨酸、α-甲基丙烯酸或丙烯酸胺、三羟甲基丙烷丙烯酸酯、甲苯作为模板分子、功能单体、交联剂和致孔剂,在较佳工艺条件下水体系中合成了色氨酸分子印迹聚合物微球;其形貌、粒径分布以及模板分子与功能单体之间的相互作用分别通过SEM、激光粒度分析仪及紫外分光光度法进行表征.其吸附能力分别通过静态吸附法测定其分离因子(α)和相对分离因子(β)来确定.实验结果表明,该法合成的色氨酸分子印迹聚合物对底物具有较高的吸附选择性和较大的吸附容量.     

超声提取南瓜多糖的研究

南瓜多糖是南瓜的活性成分,具有保健、疗疾功效。通过实验研究了预浸时间、超声功率、超声提取温度,超声作用时间以及占空比对超声提取南瓜多糖的影响和效果。结果表明：以水为提取剂,预浸时间10min,超声作用时间20min,提取温度60℃,超声波功率80W,占空比为1时,样品中南瓜多糖提取量最大可达42．6mg／g。     

Natural Antimicrobial – Containing EVOH Coatings on PP and PET Films: Functional and Active Property Characterization

Natural antimicrobials are currently being tested by many researchers for active packaging applications as a response to consumer demands for safer food products. In previous work, several packaging materials consisting of ethylene vinyl alcohol (EVOH)‐coated polypropylene (PP) films containing essential oils or their constituents as active agents were successfully developed and tested for antimicrobial activity. In this work, selected films from those materials, namely EVOH coatings with carvacrol, citral, marjoram essential oil, or cinnamon bark essential oil, on PP and polyethylene terephthalate (PET) substrates, were subjected to diverse physicochemical analyses in order to assess their suitability for food packaging applications. Concretely, the investigated properties were the stability of EVOH coatings on PP and PET substrates, the retainability of EVOH matrices for active compounds, the mechanical, optical, surface and barrier properties of the final active films and the effects of a matrix modification based on the addition of bentonite nanoclay on the performance of PP/EVOH active packages studied in actual working conditions. Results showed that the application of corona discharge followed by a polyethyleneimine‐based primer was the best anchorage treatment available to stabilize EVOH coatings on PP and PET substrates. Furthermore, they demonstrated that the retention of active agents into EVOH matrices ranged from low to moderate, depending on the embedded substance, and that their presence into an EVOH coating in the final multilayer films did not noticeably affect their mechanical, optical or barrier properties, although it considerably improved their wettability. They also indicated that the inclusion of bentonite nanoparticles into their carrier layers substantially enhanced the performance of the final packages, while maintaining or slightly improving their other physical properties. Hence, as a conclusion, all the assayed multilayer films were considered perfectly valid for food packaging applications, and the incorporation of bentonite nanoclay to their carrier layers was also highly recommended. Copyright © 2014 John Wiley & Sons, Ltd.     

Phosphorylation-induced conformational change responsible for the function of a myosin phosphatase inhibitor,CPI-17

The structures of CPI-17 (Protein kinase-C dependent protein phosphatase-1 (PP1) inhibitor of 17 kDa) in an inactive and an active form have been determined by multidimensional NMR spectroscopy. Comparison of the two structures revealed how the molecular switch turns on at atomic resolution. Using the NMR structure of CPI-17 in the active form, the binding with catalytic domain of PP1 (PP1c) was simulated and the binding model is proposed in this report. When the phospho-Thr38 docks to the catalytic site of PP1, possible interactions for the tight binding are found; one is electrostatic interaction between a negatively charged cluster on phospho-CPI-17 and an acidic groove of PP1c, and the other is hydrophobic interaction between a hydrophobic surface area of phospho-CPI-17 and a hydrophobic groove of PP1c.     

氧化锆对聚丙烯非等温结晶动力学的影响

以不同含量的氧化锆(ZrO2)作为成核剂对聚丙烯进行改性,通过差示扫描量热(DSC)方法研究改性聚丙烯的非等温结晶动力学,对所得数据分别用修正Avrami方程、Jeziorny法进行处理。实验结果表明:氧化锆的加入使聚丙烯在较高的温度下就可以产生结晶现象,氧化锆具有明显的成核作用;氧化锆的加入并未改变聚丙烯的成核和生长机理,但降低了聚丙烯的结晶活化能。     

聚乙烯亚胺修饰富勒烯的制备及其对聚丙烯热氧稳定性的影响

利用聚乙烯亚胺(PEI)分子中活泼的?NH?与富勒烯(C₆₀)结构中C=C键之间的加成反应,制备了PEI修饰C₆₀杂化物(C₆₀?PEI),并采用FTIR、TEM等测试方法对C₆₀?PEI的分子结构和形态进行表征。采用熔融共混法制备了C₆₀?PEI/聚丙烯(PP)复合材料,并对其热性能和阻燃性能进行研究。热失重分析结果表明,C₆₀?PEI可以更有效地发挥C₆₀的自由基捕捉作用,对PP热稳定性的提高效果较C₆₀更明显;氧化诱导测试(OIT)结果表明,C₆₀?PEI/PP复合材料比C₆₀/PP复合材料具有更优异的抗氧性能;微型量热测试也表明,燃烧过程中C₆₀?PEI/PP复合材料比C₆₀/PP复合材料具有更低的热释放量。      

PET-MFIAA/ PP原位成纤复合材料的形态结构及力学性能

用钉挂预埋多功能界面活化剂(MFIAA)的PET(PET-MFIAA)与PP共混 - 挤出 - 拉伸,制备了PET-MFIAA/PP原位成纤复合材料,采用扫描电镜、偏光显微镜观察和力学性能测定的方法,研究了PET-MFIAA/PP的PET微纤形态、试样断面形态及力学性能,并与PET/PP、MFIAA/PET/PP两种原位成纤复合材料进行对比。结果表明: PET-MFIAA/PP PET微纤与PP基体间具有强的相互作用,PET微纤呈粗细不均匀、凹凸不平的异形形态及柔性界面等结构特征,形成了强的界面结合,其刚性、韧性均比纯 PP明显提高,含7.00% MFIAA的PET-MFIAA/PP复合材料的拉伸屈服应力、弯曲弹性模量和悬臂梁缺口冲击强度分别达到了纯PP的1.04倍、1.23倍和1.79倍。     

新型偶联剂改性玻纤增强聚丙烯复合材料的研究

本文以硅烷偶联剂KH-560和硬脂酸为原料,通过阴离子开环反应合成出一种新的偶联剂,并将这种新型偶联剂用于玻纤增强聚丙烯。研究结果表明：这种新型偶联剂能够在玻璃纤维与聚丙烯之间引入化学键舍,明显提高了界面的粘结能力,并且使得复合材料的力学性能显著提高。     

Diffusional Behaviour of Essential Oil Components in Active Packaging Polypropylene Films by Multiple Headspace Solid Phase Microextraction–Gas Chromatography

Essential oils (EOs) are promising substances to be incorporated in food packaging materials as antioxidant and/or antimicrobial agents in active packaging systems. Once incorporated into the materials, their constituent compounds diffuse through the material. However, there is little information about the diffusion behaviour of EOs in plastics, and this is one of the major drawbacks in the design of active packaging relying on EOs as active agents. This study presents a new method for studying the diffusion of basil, citronella, oregano and rosemary EOs into plastic films. Diffusion assays of EOs from a coated polypropylene (PP) film into a stack of virgin PP films were conducted by the Moisan method using up to 10 layers of PP. Direct quantification of diffused analytes from the plastic sheets was performed by multiple headspace solid phase microextraction–gas chromatography–mass spectrometry. The fitting of experimental data for the main EO components with a Fickian model gave diffusion and partition (between active and virgin PP) coefficients, which are discussed under the light of some intrinsic factors contributing to the diffusion process. The results demonstrate the dependence of diffusion and partition coefficients on the initial concentration of EO components in the coated films, on their molecular weight and on their polarity. In particular, for similar molecular weight and initial concentration, a higher polarity is responsible for a faster diffusion, whereas lower polarity determines the retention of the EO component in the coating layer. Copyright © 2012 John Wiley & Sons, Ltd.     

接枝架桥剂配比对PP/a-PA66原位成纤复合材料形态结构和力学性能的影响

用反应性单体与助反应单体不同配比(C/R)制得的特殊结构的反应性增容剂(SCRC)与尼龙66(PA66)反应性共混,制得活性PA66(a-PA66),再将聚丙烯(PP)与a-PA66原位成纤复合,即采用"后期增容"技术,制得了一系列PP/a-PA66原位成纤复合材料,对其形态结构及力学性能进行了表征。结果表明,制SCRC时C/R过小,如2/8时,复合材料中PA66形成较均匀的微纤,但微纤与PP界面结合弱,综合力学性能不好;C/R过大,如6/4时,复合材料中PA66难以成纤,界面结合也弱,综合力学性能也不好;C/R为4/6时,复合材料中微纤的异形化程度最大,构筑成结合强的适度柔性界面,综合力学性能最佳,缺口冲击强度(NIIS)、拉伸屈服应力(TYS)、弯曲模量(FM)分别为原料PP的1.41倍、0.99倍、1.22倍。     

Investigation in Influence of Types of Polypropylene Material on Diffusion by Using Molecular Dynamics Simulation

Polypropylene (PP) and its copolymers are widely used in food packaging films and containers. This paper investigates the diffusion of limonene as a low molar mass compound through three types of polypropylene materials (PP‐H, PP‐B and PP‐R) by using the molecular dynamics method, evaluates the influence of types of polypropylene material on the diffusion behaviour of limonene and reveals the diffusion mechanism. The diffusion coefficients of limonene in PP‐H, PP‐B and PP‐R are obtained at 313K and 353K. The accessible free volumes for polymers PP‐H, PP‐B and PP‐R are calculated by using the probe radius r_p = 0.09, 0.11, 0.128 and 0.209 nm, respectively. The results suggest that not only the amount of accessible free volume in PP‐R cell model is larger than that of PP‐H and PP‐B but also the free volume in PP‐R connects together to form some larger free volume clusters. The movements of the limonene molecules through the PP‐H, PP‐B and PP‐R cell models at different simulation time suggest that for a long time the limonene molecules squirm slowly in the polymer cell rather than jumping and that the hopping diffusion is not suitable to explain the diffusion of limonene in polypropylene. The movement trajectories of the limonene molecules in PP‐R indicate that the movements of limonene in PP‐R are more active than that in PP‐H and PP‐B. The paper reveals the diffusion dynamics process and microscopic mechanism of small molecules from different types of polypropylene. Copyright © 2011 John Wiley & Sons, Ltd.