毛细管电色谱分离对映体的研究进展

本文系统评述了毛细管电色谱（ＣＥＣ）分离分析对映体的发展状况,引用文献３５篇。     

毛细管电色谱研究进展

毛细管电色谱是一种新兴的具有高效，高选择性的微分离技术。本文评述了毛细管电色说的发展状况和相关的技术，并对其发展前景进行了展望，引用文献２４篇 。     

反相毛细管电色谱中无盐体系的优势及分离研究

本文将电中性溶质在缓冲盐体系和无盐体系下的电渗流、分离选择性等进行了对比,从理论和实验两方面讨论了电中性溶质在无盐体系下的分离,提出了采用无盐流动相既可以增加电渗流也可以减小焦耳热的优势。反相毛细管电色谱的实验结果也充分证明了这一点。     

The Development of Reversed‐Phase Capillary Electrochromatography for the Separation of Steroids

This paper describes the preparation and optimization of packed capillary columns for reversed‐phase separation of steroids with CEC. The fabrication of on‐column frits is considered to be the most important step for obtaining a reproducible packed column for CEC separation. Porous silicate frits were generated in a fused‐silica capillary by heating the silica gel/sodium hydroxide solutions electrically. The optimized conditions involve silica gel (10.8%), sodium hydroxide (5.8%), and heating time (5 sec) with heating voltage (5V) for obtaining a 100‐μ end‐frit that can withstand pressure over 6000 psi. A HPLC pump was utilized to pack the 5‐μm ODS particle slurry into the capillary column. The ODS packed capillaries were then utilized for the separation of four anabolic cholesterols with a capillary electrophoresis system without pressurization of the column. The reproducibility of the packed columns was evaluated by measuring the relative standard deviations of four steroids. The relative standard deviations of migration time for column‐to‐column, day‐to‐day, and run‐to‐run are less than 7%, 2%, and 1% for four steroids, respectively.     

用强阴离子交换毛细管电色谱分离阴离子化合物

对阴离子性化合物在强阴离子交换毛细管电色谱中的保留行为进行了研究。发现样品中固定相上的吸附使样品的保留因子k^*变小,柱小的分离能力减小;而电压的增大,使酸性样品的k^*也增大,并且电压的改变也能改变分离的选择性;样品保留因子的对数值随着缓冲液离子强度的对数值的增大而线性减小;样品也强阴子交换毛细管电谱和毛细管区带电泳中有不同的保留行为。     

毛细管电色谱有机流动相双二元双台阶分离

根据毛细管电色谱中溶质保留值与有机改性剂种类和浓度之间的相互关系，首次实现了毛细管电色谱有机流动相双二元双台阶分离。利用此方法分离含１２种芳香族化合物的混合样品，各组分在六次连续进样中保留时间的ＲＳＤ（％）值均在１．６５％以内，并将样品的分离时间缩短到等度洗脱方式下的三分之一。这说明该方法分离复杂样品快速、可靠。此外还推导了双二元双台阶分离方式下溶质保留值的预测公式，并对该公式的准确性进行了检验，预测值与实测值间的相对误差在５．７３％以内。     

开管毛细管电色谱进展

开管毛细管电色谱是近年发展起来的一种高效、快速的新型微柱分离方法。它是在毛细管管壁涂布或键合固定相,以电渗流驱动流动相的一种色谱分离模式。该文对开管毛细管电色谱的发展、柱制备、理论进行了较为详细的综述,引用文献４７篇     

分子印迹毛细管电色谱整体柱研究进展

从分子印迹毛细管电色谱整体柱的基本原理入手,介绍了毛细管的预处理方法;讨论了色谱柱制备过程中,印迹分子、功能单体、交联剂、引发剂、溶剂的选择以及比例的影响;比较了光引发及热引发两种聚合方式的特点;阐述了聚合时间、聚合温度的控制;并探讨了色谱分析过程中检测电压、检测温度、流动相组成等操作条件的影响。最后介绍了分子印迹毛细管电色谱整体柱领域一些新的研究方向,并对其今后的发展进行了展望。     

Transition Metal-Mediated Separation of Isomeric Pneumocandins by Capillary Electrochromatography

The novel separation of a 3-hydroxyproline containing a semi-synthetic macrocyclic antifungal agent from its structurally related 4-hydroxyproline isomer using capillary electrochromatography (CEC) is described. The molecular weight of the two compounds is 1093 Daltons and they differ only in the placement of a proline -OH group. The separation is achieved using capillaries packed or coated with ODS particles (C18) or with glycerol bound to silica through a carbon chain linker. The presence of a transition metal (Ni(II), Ag(I), Zn(II), or Cu(II)) as buffer additive in the phosphate buffer (pH=2.5):CH₃CN (75:25, v/v) is essential to achieve a baseline separation. HPLC columns packed with similar ODS particles showed no selectivity. Capillaries packed or coated with C18 material under similar conditions showed partial selectivity compared to the glycerol capillaries. Some fundamental aspects of CEC, such as capillary temperature, applied voltage, and buffer composition were varied in order to study the mechanism of the separation. This mechanistic study included the testing of first and second row transition metal ions (individually or in combination), the use of organic solvents, the use of an ion pair reagent, and the use of β- and γ-cyclodextrin to assess the impact on the separation. The resolution was dependent on the metal ion concentration and is consistent with a mechanism of metal-oxygen complexation through the hydroxyl groups of the two isomers and glycerol.     

毛细管电色谱-质谱联用技术进展

毛细管电色谱-质谱联用技术结合了毛细管电色谱高分离性能和质谱强定性能力的特点，近年来得到较快的发展。本文系统综述了CEC/MS接口技术及在复杂样品分离分析中应用的最新进展。引用文献45篇。     

液晶修饰的有机-无机杂化硅整体柱的制备及电色谱性能

合成了一种含有端烯基的液晶4'-(ω-十一烯基氧)-4-联苯酚,通过偶氮二异丁腈(AIBN)引发的自由基聚合反应将其用于修饰含有烯基的有机-无机杂化硅整体柱.将该整体柱应用于毛细管电色谱,成功分离了萘酚、多环芳烃、酞酸酯和甾体激素,与未修饰柱的分离效果进行比较发现,疏水作用、π-π作用和氢键作用是导致分离的主要原因.以...     

离子液体修饰的杂化硅整体柱的制备及其电色谱性能

合成了含有烯丙基的离子液体氯化1-烯丙基-3-甲基咪唑(AMIMCl),采用自由基聚合反应将其固定到含有乙烯基的杂化硅整体柱表面,制备了离子液体修饰的杂化硅整体柱.在酸性环境下,利用该整体柱分离了核苷酸、酚类物质和苯甲酸类化合物,与未进行修饰的整体柱相比,离子液体修饰的杂化硅整体柱的电渗流反向,分离选择性明显提高,这可...     

Investigation into the Formation of Bubbles in Capillary Electrochromatography

The formation of bubbles in capillary electrochromatography (CEC) is well documented: possible origins include Joule heating and variations in EOF velocity on passing from the stationary phase through the frit and into the open tube. Methods for the prevention of bubble formation are discussed which are confirmed by experimental results. Using frit lengths varying from 1 mm to 6 mm it is shown how frit length is directly related to the likelihood of bubble formation and how this is affected by applied voltage. It is shown that the change in applied voltage across a capillary affects the formation of bubbles and also that rebonding octadecylsilane (ODS) onto the silica frit after formation of the frit can minimize the formation of bubbles and how this effects the chromatography. A method is also described for increasing the robustness of silica capillaries using a column coupler along with modifications made to conventional capillary electrophoresis equipment to cater for CEC.     

Preparation and Porous Property of C14-Monolithic Column for Capillary Electrochromatography

Capillary electrochromatography (CEC) has been performed with a series of C₁₄, methlyacrylamide based monolithic columns. These monoliths with different porosities were prepared by in-situ copolymerization in fused-silica capillaries. The porous properties of monoliths were further observed using scanning electron micrographs (SEM) and measured using a mercury porosimeter. The effect of various alcohols as porogens on porous structural properties and chromatographic behaviors were also investigated. The effects of organic additive, pH value and ionic strength in mobile phase on electroosmosis flow (EOF) and separation were further discussed. Meanwhile, the baseline separation of 6 neutral compounds can be well obtained. In addition, the monolithic column demonstrates the high column efficiency and satisfactory reproducibility.Acknowledgements We gratefully acknowledge the support of the National Natural Science Foundation of China.     

Rapid Preparation of Monolithic Columns for Capillary Electrochromatography Separation

Sol-gel technology can provide a versatile approach to the synthesis of organic polymers and organic-inorganic hybrid materials applied in HPLC, micro-HPLC and capillary electrochromatography (CEC)1. It can take place under extraordinarily mild thermal co…     

吸附固定相电色谱和动态改性电色谱的手性分离

对动态改性电色谱手性分离进行了研究。电色谱柱填充强阴离子交换固定相（SAX0,添加在流动相中的磺化β－环糊精（S－CD）动态地吸陵于SAX填料表面,形成一层准手性固定相。色氨酸、阿托品和异博定对映体在本体系获得了很好的分离,它们的分离分别为2．06,10．1和1．96,对映体峰的柱效价于85,000塔板数／米和412,000塔板数／米之间。连续运行17次,死时间和色氨酸对映体的电色谱保留因子的相对标准偏差分别为0．53％,0．62％和0．69％。此外,以吸附于SAX填料的牛血清白蛋白和S－CD为手性固定相进行了电色谱手性分离的研究。在这两种体系下分离色氨酸对映体的分离度分别为3．86和2．97。吸附S－CD柱电色谱和动态改性电谱的重现性进行子比较,发现动态改性电色谱有更好的重现性。     

Preparation of Fritless Packed Silica Columns for Capillary Electrochromatography

Fritless packed silica gel columns were prepared using sol‐gel technology. A part of a 75 μm i.d. fused silica capillary was filled with a mixture of tetramethoxysilane and poly(ethylene glycol). After gelling at 40°C and heating at 300°C, the resultant silica gel was derivatized with dimethyloctadecylchlorosilane. A scanning electron micrograph of a cross‐section of the capillary column showed that the gel took the form of a spherical particle aggregate and adhered to the column inner wall. The column performance was evaluated for electrochromatography using acetonitrile–50 mM HEPES buffer (pH 6.6) (60/40 or 40/60, v/v) as the mobile phase. An electroosmotic flow of 1.0 mm/s was generated with (60/40, v/v) acetonitrile/HEPES buffer at a field strength of 546 V/cm. Using a sol‐gel‐derived packed column at an electroosmotic flow of 0.5 mm/s, efficiencies of up to 1.1×10⁵ plates/m were obtained for retained solutes.     

Capillary Electrochromatography on Methacrylate Based Monolithic Columns: Evaluation of Column Performance and Separation of Polyphenols

Fused-silica capillary columns (100 μm I.D.) englobing a porous monolithic stationary phase were prepared by in situ copolymerization of 2-ethylhexyl methacrylate, ethylene glycol dimethacrylate and 2-acrylamido-2-methylpropanesulfonic acid (AMPS) in the presence of a porogenic mixture containing 1-propanol, 1,4 butanediol and water. The influence of the monomers ratio and the porogen solvent composition as well as the content of AMPS in the polymerization mixture on column total porosity and efficiency was investigated to attain minimum HETP values for the reversed-phase capillary electrochromatography separation of bioflavonoids. For the most promising column, the van Deemter plots, in both μ-HPLC and CEC, were also evaluated. In CEC the reduced plate height was found almost constant (1.6–2.0) within the range of linear mobile phase velocity between 0.2–2.0 mm s⁻¹. The chemical and mechanical stabilities of the monolithic column over a wide range of buffer pH (2-10) and time were satisfactory. Furthermore, the effects of mobile phase parameters, such as buffer concentration and organic modifier content, on the electroosmotic flow were studied systematically. CEC separations of standard mixtures of polyphenols, including flavonols, flavanones and flavanones-7-O-glycosides, were accomplished in less than 8 min. The CEC separation of the major flavanone glycoside constituents in the extract from a freshly squeezed grapefruit juice was also reported.     

双动态吸附毛细管电色谱的手性分离——采用阳离子表面活性剂和阴离子手性选择剂作为假固定相

建立了以十六烷基三甲基溴化铵或1,5－二甲基－1,5－二氮杂十一烷亚甲基聚N－甲溴化物为阳离子表面活性剂,并以磺丁基β－环糊精为手性选择剂的双动态吸附毛细管电色谱。以碱性的丙比胺和酸性的华法林作为拆分对象,考察了双动态吸附毛细管电色谱的手性分离行为,以及动态吸附柱的重复性。在双动态吸附毛细管电色谱条件下,丙比胺和华法林的手性分离度较大,丙比胺的分离度可达3．21,丙比胺连续进样10次,迁移时间的相对标准偏差小于1．0％。     

毛细管电色谱法的研究进展

比较全面地综述了毛细管电色谱法的发展及研究状况。