窄内径多孔层开管柱的制备及在液相色谱中的应用

近年来,微纳分离技术由于其内在的优势而受到越来越多的关注.多孔层开管柱是一种重要的微分离柱形式,与粗内径的多孔层开管柱(>25μm)相比,窄内径的多孔层开管柱具有更高的分离效率和更低的试剂消耗量.本文综述了内径≤25μm的窄内径多孔层开管毛细管柱的制备方法、与质谱检测联用技术以及在液相色谱中的应用研究进展,对其发展前景进行了展望.     

新型聚合物多孔涂层毛细管开管柱的制备及电色谱研究

以甲基丙烯酸缩水甘油酯(GMA)和乙二醇二甲基丙烯酸酯(EDMA)为前驱体制备了新型聚合物多孔涂层毛细管开管(PLOT)柱固定相。通过优化聚合反应时间、致孔剂比例及交联剂比例获得了色谱性能良好的PLOT柱,扫描电镜结果显示毛细管柱内的多孔涂层厚度适中且均匀。在毛细管电色谱模式下,PLOT柱以反相色谱分离机理有效分离了中性、酸性和碱性小分子。人血清白蛋白(HSA)共价结合的蛋白亲和PLOT柱对5对手性对映体实现了较好的分离,且其分离度远高于HSA修饰的单层聚合物毛细管开管柱。PLOT柱分离烷基苯的日内、日间和柱间的相对标准偏差分别小于1.7%、4.8%和7.8%。     

纳米硅胶多孔层毛细管气相色谱柱的原位溶胶-凝胶法制备及其应用

采用原位溶胶-凝胶法在毛细管内壁上合成出均匀的纳米硅胶多孔层,对纳米硅胶颗粒进行了形貌表征,同时考察了不同反应条件下合成的纳米硅胶的比表面积、孔容和孔径的变化规律。先采用含氢硅油高温键合固化硅胶层,然后用无机盐淋洗钝化毛细管色谱柱,制备出纳米多孔层硅胶毛细管色谱柱。考察了所制备的纳米多孔层硅胶毛细管色谱柱对挥发性氟氯烃、水中氯代烃、含硫化合物以及低碳烃的分离特性。结果表明:所制备的纳米多孔层硅胶毛细管色谱柱具有良好的分离能力、一定的抗水性、稳定的色谱保留特性和良好的制柱重复性。     

原位聚合法制备碳十八甲基丙烯酸酯聚合物及其用作开管毛细管电色谱固定相

以十八碳醇甲基丙烯酸酯为单体、乙二醇二甲基丙烯酸酯为交联剂,采用原位聚合法合成了一种新型毛细管开管柱固定相,优化了毛细管开管柱的制备参数。柱内表面的电镜图像显示其具有多孔皱褶、质地均匀的结构特征。将其应用于甲苯、乙苯、丙苯、丁苯、戊苯和己苯的分离试验中,6种化合物达到了完全分离,出峰顺序与它们的疏水性一致,表明该柱有明显的疏水色谱作用。在10 mmol/L磷酸盐(pH 8.5,含50%(v/v)乙腈)流动相、16 kV电压下,该开管柱成功地分离了4种抗癫痫类药物,柱效范围为35300~49800 塔板/m,与空柱管相比分离效果明显提高。结果表明通过本实验的原位聚合法可制备具有反相色谱作用的有机基质碳十八开管毛细管电色谱柱。     

混合烷基开管电色谱柱的制备和评价

利用溶胶－凝胶（Sol-Gel）技术制备了混合烷基开管毛细管电色谱柱（C8－C13OT－CEC），并考察了其电渗流行为和电色谱性能。研究了流动相中甲醇含量对芳香族中性化合物保留的影响。发现C8－C18OT－CEC柱体现反相分配机理。5种芳香族化合物和4种苯同系物在C8－C13OT－CEC柱上分离良好，同时还考察了分离电压和柱内径对柱效的影响，结果表明高的电压和较小的柱内径能提高柱效。     

新型二氧化硅纳米毛细管开管柱的制备及其电色谱性能的研究

本文通过原位聚合反应合成了一种基于纤维状二氧化硅纳米(fSiO_2)和聚合物(DMAEMA polymer)的材料(P-fSiO_2),将该材料采用物理吸附的方式涂覆到毛细管内壁,制备了新型的毛细管电色谱开管柱(P-fSiO_2开管柱),并将其应用于磺胺类物质的开管毛细管电色谱(OT-CEC)分离分析。P-fSiO_2开管柱的制备方法简便快捷、涂层稳定、重复性好,其中日内相对标准偏差(RSD)值小于4.3%(n=6),日间RSD小于4.9%(n=6),柱间RSD为2.2%(n=5)。通过对缓冲溶液浓度、pH值以及分离电压等因素的考察,可以实现对8种磺胺类化合物的良好分离,其中磺胺喹恶啉(SQX)的柱效高达228 542 N/m。     

微波辅助合成法快速制备替考拉宁开管毛细管电色谱柱

采用微波辅助合成技术,快速制备了以替考拉宁为固定相的开管毛细管电色谱柱。在pH 4.0~7.0的范围内比较了空管与替考拉宁修饰柱的电渗情况,表明替考拉宁开管毛细管电色谱柱有效地降低了电渗。用该色谱柱分离了多种手性对映体,均达到基线分离,体现了替考拉宁开管毛细管电色谱柱良好的分离性能。以DL-色氨酸考察了柱子的稳定性和重现性,结果显示采用微波辅助合成技术制得的替考拉宁开管毛细管电色谱柱具有良好的稳定性和重现性。     

高效多孔层毛细管柱吸附气相色谱的研究进展

PLOT柱是用于永久性气体,低碳烃和挥发性化合物色谱分析的最有效的工具,经常用于替代经典填充柱,对多孔层开管毛细管柱（PLOT）吸附色谱的分离机理、PLOT柱制备方法和各类吸附剂的色谱特性及其特定应用进行了综述。     

连续二维开管离子交换/反相整体柱毛细管电色谱的构建与评价

在毛细管中原位合成反相整体色谱柱,并在同一根毛细管柱中的其余部分通过在内表面涂覆N-[3-(三甲氧基硅烷)-丙基)]-乙二胺(PEDA)使其具有离子交换功能,制备成连续二维开管离子交换/反相整体柱毛细管电色谱柱.通过对7种有机酸的分离探讨了开管柱中离子交换对分离的影响,进一步以天麻提取物为样品,对二维分离系统加以评价,...     

不锈钢高温毛细管色谱柱的研制

〕以甲硅烷高温裂解的方法钝化不锈钢毛细管内表面。用钝化后的柱管制备了涂渍固定液的开管柱(WCOT)和固体吸附剂的多孔层开管柱(PLOT),两种柱子都能在400℃以上的高温操作,并在石油化工分析中得到应用。不锈钢高温毛细管柱的出现,解决了弹性石英毛细柱在高温下容易断裂的问题。     

新型有机-无机杂化整体柱的制备及其在毛细管液相色谱及加压毛细管电色谱中的应用

以丙烯酰胺(AM)为单体,八乙烯基倍半硅氧烷(POSS)为交联剂,偶氮二异丁腈(AIBN)为引发剂,四氢呋喃(THF)为致孔剂,通过原位聚合法制备了poly(POSS-co-AM)有机-无机杂化整体柱,并对各反应物的配比进行了优化。结果表明,当功能单体与致孔剂、POSS与AM的质量比均为1.0: 5.0, AIBN的质量分数为0.1%时,杂化整体柱的柱效最高。无机材料的引入使整体柱结构均匀并具有良好的渗透性,该整体柱既能用于亲水色谱模式,也能用于反相色谱模式。将制备的整体柱用于毛细管液相色谱和加压毛细管电色谱分离核苷类、胺类、硝基苯胺类等化合物,获得了良好的效果。     

Polymetacrylate and hybrid interparticle monolithic columns for fast separations of proteins by capillary liquid chromatography

Preparation of organic polymer monolithic columns in fused silica capillaries was aimed at fast gradient separation of proteins. For this purpose, polymerization in situ procedure was optimized, using ethylene dimetacrylate and butyl metacrylate monomers with azobisisobutyronitrile as initiator of the polymerization reaction in presence of non-aqueous porogen solvent mixtures composed of 1-propanol and 1,4-butanediol. The separation of proteins in totally monolithic capillary columns was compared with the chromatography on a new type of "hybrid interparticle monolithic" capillary columns, prepared by in situ polymerization in capillary packed with superficially porous spherical beds, 37-50 microm. The "hybrid" columns showed excellent stability and improved hydrodynamic flow properties with respect to the "totally" monolithic capillary columns. The separation selectivity is similar in the two types of columns. The nature of the superficially porous layer (bare silica or bonded C18 ligands) affects the separation selectivity less significantly than the porosity (density) of the monolithic moiety in the interparticle space, controlled by the composition of the polymerization mixture. The retention behaviour of proteins on all prepared columns is consistent with the reversed-phase gradient elution theory.     

Towards stationary phases for chromatography on a microchip: molded porous polymer monoliths prepared in capillaries by photoinitiated in situ polymerization as separation media for electrochromatography

Photoinitiated free radical polymerization has been used for the preparation of porous polymer monoliths within UV transparent fused silica capillaries and quartz tubes. These formats were used as models for the preparation of the separation media within channels of microfabricated devices. A mixture of ethylene dimethacrylate, butyl methacrylate, and 2-acrylamido-2-methyl-1-propanesulfonic acid was polymerized in the presence of a porogenic solvent consisting of 1-propanol, 1,4-butanediol, and water at room temperature under UV irradiation. Modification of the porogen composition enables the tailoring of pore size within the broad range from ca. 100 to 4000 nm. Scanning electron micrographs confirmed the homogeneity of the porous structure of the materials prepared, even in a quartz tube with a diameter as large as 4 mm. Separation properties of the resulting capillary columns were tested in capillary electrochromatography (CEC) mode using a mixture of thiourea and eight aromatic compounds. Plate number as high as 210 000 plates/m were found for a capillary column with optimized porous properties. The monolithic columns were also able to separate mixtures of peptides.     

TEMPO调控下的苯乙烯光聚合

在UV光照射下, 以Irgacure 1103/TEMPO为引发剂, 实现了苯乙烯的低温光引发可控聚合, 得到了低分散性的聚苯乙烯. 与热引发聚合相比较, 光聚合的反应条件更温和, 聚合速率更快. 探讨了聚合体系中光引发剂及光强等因素的影响, 实现了光聚合产物的扩链反应.     

Recent advances in the control of morphology and surface chemistry of porous polymer-based monolithic stationary phases and their application in CEC

This review focuses on developments in the field of polymer-based monolithic columns for CEC published in the literature since the beginning of the year 2005. The possibility of in-situ preparation as well as easy control over their porous properties and surface chemistries clearly make monolithic separation media an attractive alternative to capillary columns packed with particles. Different variables such as polymerization conditions, morphology, and surface chemistry are shown to directly affect performance of monolithic capillary columns in terms of efficiency, analysis time, and retention.     

氧化石墨烯修饰多孔复合涂层超长开管液相色谱柱的制备与评价

采用原位聚合法在毛细管柱(3 m ×25μm i. d.)内壁制备粗糙结构的聚氯甲基苯乙烯二乙烯基苯涂层,并将氧化石墨烯以共价键合的方式固定在涂层表面,制备成氧化石墨烯修饰多孔复合涂层超长开管毛细管液相色谱柱。通过扫描电镜、透射电镜、拉曼光谱等手段对固定相的结构进行表征,证实聚氯甲基苯乙烯二乙烯基苯涂层具有球形分散结构,而片状的氧化石墨烯均匀覆盖在聚合物层表面。球状的聚合物层及氧化石墨烯的覆盖极大地提高了色谱柱的相比及样品容量,乙腈-水为流动相可分离烷基苯、中性多环芳烃、酸性和碱性化合物,乙腈-0.02 mol/ L 醋酸铵为流动相可实现4种核酸碱基样品的分离。制备的色谱柱具有良好的重复性和稳定性,测试的日内、日间、柱间重复性(n=6)相对标准偏差(RSD)均在0.3%~2.0%范围内。     

A model of flow-through pore formation in methacrylate ester-based monolithic columns

The main factors affecting the porosity of methacrylate-ester based monolithic columns were investigated. We prepared 23 monolithic capillary columns with porosity controlled by varying the proportions of butyl methacrylate and ethylene dimethacrylate monomers and of 1,4-butanediol and 1-propanol as the porogen solvent in the polymerization mixtures by thermally initiated in-situ polymerization in fused-silica capillaries. Using mixture design software, we systematically varied the composition of the polymerisation mixtures to find significant factors affecting flow-through pore formation. Multivariate analysis of the experimental data obtained for the fabricated columns yielded a model for prediction of the flow-through porosity in monolithic beds as a function of the composition of the polymerization mixture used to prepare polymethacrylate monolithic capillary columns. The mean error of prediction was lower than 8% for eight columns prepared independently of the original set of 15 columns used to derive the flow-through model. The flow-through porosity increases with increasing concentration of the binary porogen solvent mixture, the concentration of 1,4-butanediol being the main factor enhancing flow-through pore formation. On the other hand, increasing concentrations of the hydrophobic monomer butyl methacrylate and increasing concentrations of 1-propanol have a negative effect on flow-through pore formation. The capillary columns prepared with a high proportion of flow-through pores and a minimum amount of mesopores can be used for fast gradient separations of both low-molecular weight compounds and biopolymers.