以万古霉素为手性选择剂的氨基酸对映体的毛细管电泳快速分离

建立了以万古霉素为手性分离选择剂的毛细管电泳氨基酸对映体快速分离的方法。向缓冲溶液中加入０．００２％（Ｗ／Ｖ）的（１,５－二甲基－１,５－二氮杂十一烷亚甲基聚Ｎ－甲溴化物（ｈｅｘａｄｉｍｅｔｈｒｉｎｅ ｂｒｏｍｉｄｅ ＨＤＢ）做电渗流改性剂,使电渗流的迁移方向反转,与分析物方向一致,缩短了分析时间。此外,ＨＤＢ还使毛细管壁得到动态修饰,减少了万古霉素在毛细管壁上的吸附,从而提高了柱效。考察了缓冲溶     

5—氨基水杨酸锌及相关物质的高效毛细管电泳分离与测定

１引言５－氨基水杨酸是治疗胃溃疡和Ｃｒｏｈｎ疾病的药物。为提高稳定性和药物疗效，最近合成了新药物５－氨基水杨酸锌。我们对５－氨基水杨酸锌与主要杂质水杨酸，以及可能降解产物５－氢基水杨酸与对氨基苯酚等物质的高效毛细管电泳（ＨＰＣＥ）的分离与测定进行了研究，结果表明，本法分离效果好，测定准确，具有较好的应用价值。２实验部分１２２９ＨＰＣＥＡＮＡＬＹＳＥＲ（北京新技术应用研究所），石英毛细管（６５．５ｃｍ×５０μｍｉ．ｄ，有效长度５７．３ｃｍ，河北永年光纤厂）。５－氨基水杨酸锌（ＺｎＡＳＡ，９９％），…     

水杨酸及其氯代物的毛细管电泳分析研究

建立了分析水杨酸、５－氯代水杨酸、三氯水杨酸等水杨酸类化合物的毛细管区带电泳法（ＣＺＥ）。讨论了电压、缓冲溶液的浓度和ｐＨ值对分析结果的影响。其中缓冲溶液的ｐＨ值对分析结果的影响最为显著。ｐＨ〈７．４０时,三种化合物的出峰顺序为：三氯水杨酸、５－氯代水杨酸、水杨酸;当ｐＨ〉７．４０时,三种化合物的出峰顺序为：５－氯代水杨酸、水杨酸、三氯水杨酸。水杨酸、５－氯代水杨酸、三氯水杨酸的检出限分别为０．１     

丁基胺丙基硅胶毛细管整体柱的制备及其电色谱性能研究

采用溶胶-凝胶技术制备了丁基胺丙基硅胶毛细管整体柱,此整体固定相表面同时含有能产生阳极的电渗流的仲胺官能团和产生疏水作用的正丁基和丙基官能团。对所制备的整体柱电色谱性能进行了详细的表征和分析。考察了流动相pH值对电渗流的影响;对烷基苯同系物、有机酸酸性化合物和苯胺类碱性化合物保留行为进行了研究,并对其可能的保留机理进行了探讨。实验结果表明,对于中性化合物的保留机理主要基于反相作用;而对于酸性化合物的保留行为则是基于混合模式作用机理,即除了电泳作用外,还包括阴离子交换和疏水作用。碱性化合物在丁基胺丙基硅胶毛细管整体柱上的峰形较好,没有明显的峰拖尾现象。     

5-氨基水杨酸锌及相关物质的高效液相色谱分析研究

对５－氨基水杨酸锌及相关物质５－氨基水杨酸、水杨酸、对氨基苯酚和５－苯偶氮基水杨酸的高效液相色谱法（ＨＰＬＣ）的分离条件进行了优化研究,结果表明,采用ＣＬＣ－ＯＤＳ（１５０ｍｍ×６．０ｍｍｉ．ｄ．,１０μｍ）作为分离柱,１％（Ｖ／Ｖ）ＨＡｃ－ＭｅＯＨ（４∶６）作为流动相,在流速为１ｍＬ／ｍｉｎ的情况下,上述５种物质在１０ｍｉｎ内可以达到基线分离,保留时间的日内和日间的变异系数分别小于２％和５％,在一定浓度范围内,浓度与峰面积的线性关系良好。     

毛细管电泳的原理及应用（第三讲）毛细管电泳的柱技术

毛细管电泳的原理及应用（第三讲）毛细管电泳的柱技术王义明,罗国安（清华大学化学系,清华大学生命科学与工程研究院北京１０００８４）关键词毛细管电泳,柱技术１概述毛细管电泳（ＣＥ）的分离和检测过程均在毛细管内完成,所以说毛细管是ＣＥ的核心部件之一。早期对毛细管的研究集中在毛细管直径、长度、形状和材料方面。采用细柱可减少电流及自热,而且能加快散热,以保持高效分离;但会造成进样、检测及清洗上的困难,也不利于对吸附的抑制,故现在一般采用２５～１００μｍ内径的毛细管。     

低电渗流毛细管区带电泳分离芳香胺

利用低pH值（pH≤2.0）有效地抑制电渗流,建立起低电渗流毛细管区带电泳(CZE)体系,并分离了7种芳香胺。在此体系中,芳香胺质子化而带正电荷,故采用在毛细管阳极端进样,阴极端检测。实验考察了pH值、电解质浓度对分离的影响,结果发现,当pH＜p K a （p K a =14-p K b ）时,pH值的微小增大会导致芳香胺的迁移时间迅速延长;芳香胺的出峰次序与其p K b 值及分子中含有的胺基和酸性取代基的数目有关,分子中含胺基愈多,p K b 值愈小,出峰愈早;芳香胺含酸性取代基则使峰序滞后。     

不同价态铬离子的毛细管电泳分离与测定

１引言由于元素的不同价态、不同存在形态具有不同的物理、化学性质与生理活性。如Ｃｒ（Ⅲ）是人体必需的元素，而Ｃｒ（Ⅵ）则是有害的。因此，离子的价态分析具有十分重要的意义。由于毛细管电泳可实现阴阳离子的同时分析，与离子色谱相比，具有简单、快速的特点。本文采用样品与ＥＤＴＡ络合的办法，用毛细管电泳在ＣＨ３ＣＯＯＮａ－ＣＨ３ＣＯＯＨ体系中（含电渗流改性剂和络合剂），对ＣｒＯ４２－、Ｃｒ３＋的分离测定进行了研究。用直接紫外法检测在５．５ｍｉｎ内可完成两种价态铬离子的测定，特别适于电镀废液或其它水质的分析。…     

弛豫理论对离子交换毛细管电色谱中峰压缩现象的研究

 在毛细管电色谱中,由于溶质在输运过程中所具有的电性质,常会产生一些特殊的现象。这些现象,如离子交换毛细管电色谱中产生超高柱效峰的现象,已经不能用一般的色谱理论加以解释。基于弛豫理论所建立的基本模型,在考虑溶质在两相中皆有可能发生正、反向迁移的情况下,得到了流出曲线一阶原点矩和二阶中心矩的理论表达式,并通过对溶质在两相中电扩散速率与电泳速率、电渗流速率关系的分析结果证实:溶质在固定相表面的电扩散行为可以使其保留变弱,出峰加快;而这种电扩散导致的超常柱效峰的出现具有不稳定性,只有在多方面因素综合影响匹配的情况下才可能出现。     

毛细管区带电泳峰形变化规律的研究

采用指数修正的高斯模型（ＥＭＧ）,研究了进样时间、分离电压及柱长等一系列操作条件对毛细管区带电泳峰形参数的影响。实验结果表明,进样时间对半峰宽（Ｗ１／２）和峰不对称度（Ｂ／Ａ）有显著影响;电压对以长度表示的半峰宽及峰拖尾参数无显著影响;ｔｍ与σ、τ、Ｗ１／２（ｓ）之间都有很好的线性关系;随着柱长的增大,σ、τ、Ｗ１／２都略有增加。     

羟基苯甲酸的3种异构体的毛细管区带电泳分离研究

 采用十六烷基三甲基溴化铵 (CTAB)为电渗流改性剂 ,考察了邻羟基苯甲酸、间羟基苯甲酸和对羟基苯甲酸在高效毛细管区带电泳模式下的分离行为 ,研究了缓冲液的pH和添加剂甲醇的用量对这 3种同分异构体的分离、峰形和出峰顺序的影响 ,并据此优化了这 3种异构体的分离条件。     

Large volume sample stacking of positively chargeable analytes in capillary zone electrophoresis without polarity switching: use of low reversed electroosmotic flow induced by a cationic surfactant at acidic pH

A simple and effective way to improve detection sensitivity of positively chargeable analytes in capillary zone electrophoresis more than 100-fold is described. Cationic species were made to migrate toward the cathode even under reversed electroosmotic flow caused by a cationic surfactant by using a low pH run buffer. For the first time, with such a configuration, large volume sample stacking of cationic analytes is achieved without a polarity-switching step and loss of efficiency. Samples are prepared in water or aqueous acetonitrile. Aromatic amines and a variety of drugs were concentrated using background solutions containing phosphoric acid and cetyltrimethylammonium bromide. Qualitative and quantitative aspects are also investigated.     

Separation and determination of 10-hydroxy-2-decenoic acid in royal jelly by capillary electrophoresis

Summary The application of capillary electrophoresis (CE) to the separation and determination of the active ingredient, 10-hydroxy-2-decenoic acid, in royal jelly with direct on-column UV detection at 214 nm is described. Using a cathodic injection and anodic detection scheme, 10-hydroxy-2-decenoic acid (10-HDA) was separated and detected in less than 10 min in a fused silica capillary column with a phosphate buffer at pH 7.3 with an applied voltage of 20 KV followed by direct UV detection. The use of cetyltrimethylammonium bromide (CTAB) as electroosmotic flow modifier allows the rapid separation of 10-HDA from other constituents in royal jelly by reversing the direction of electroosmotic flow. The influence of organic solvents in the electrolyte on separation selectivity is also discussed.     

卤代乙酸及其结构相近化合物的高效毛细管电泳分离

氟、氯、溴等卤代乙酸是结构非常相近的离子型化合物,对它们的分离测定比较困难。用高效毛细管电泳法在碱性或酸性缓冲液条件下可将它们分离。在酸性缓冲液条件下,可提高有机酸分离的选择性。较低的操作电压有利于提高阴离子的分离度,而改变温度对分离度的影响不大。     

Separation of peptides and proteins by capillary electrophoresis using acidic buffers containing tetraalkylammonium cations and cyclodextrins

A method for improving separations of peptides and other positively charged species in capillary zone electrophoresis with untreated capillaries using acidic buffers containing tetraalkylammonium cations is described. Tetramethylammonium and tetrabutylammonium cations dynamically modify the capillary surface, leading to a reversal in the direction of the electroosmotic flow. As a result, the adsorption of positively charged peptides and proteins is minimized, and resolution and peak capacity are improved as the migration of cationic analytes is counterbalanced by the electroosmotic flow. The combining effect of reversing electroosmotic flow and cyclodextrin inclusion complexation on separations of closely related peptides and a protein mixture, as well as tryptic digest of hemoglobin is demonstrated.     

Separation of the positional isomers of phthalic acids in hydroorganic solvents using capillary electrophoresis

The positional isomers of phthalic acids (ortho-, meta-, and para-) and benzoic acid could be completely separated by capillary electrophoresis (CE). A simple CE method employing direct detection in mixed methanol/water buffers is presented. The effect of the electrolyte buffer system, including pH, buffer concentration, and organic solvent on the electrophoretic mobility of the analytes, is investigated. The electroosmotic flow is reversed using cationic surfactant and cetyltrimethylammonium bromide so that anions are separated under the co-EOF mode. The resolution of the analytes and selectivity could be improved by the adjustment of the methanol content. Ion association with the surfactant in methanol/water buffer is discussed. The validity of the method in terms of sensitivity, reproducibility, and linearity is also reported. The text was submitted by the authors in English.     

Separation of basic, acidic and neutral compounds by capillary electrochromatography using uncharged monolithic capillary columns modified with anionic and cationic surfactants

A mode of capillary electrochromatography (CEC), based on the dynamical adsorption of surfactants on the uncharged monolithic stationary phases has been developed. The monolithic stationary phase, obtained by the in situ polymerization of butyl methacrylate with ethylene dimethacrylate, was dynamically modified with an ionic surfactant such as the long-chain quaternary ammonium salt of cetyltrimethylammonium bromide (CTAB) and long-chain sodium sulfate of sodium dodecyl sulfate (SDS). The ionic surfactant was adsorbed on the surface of polymeric monolith by hydrophobic interaction, and the ionic groups used to generate the electroosmotic flow (EOF). The electroosmotic mobility through these capillary columns increased with increasing the content of ionic surfactants in the mobile phase. In this way, the synthesis of the monolithic stationary phase with binary monomers can be controlled more easily than that with ternary monomers, one of which should be an ionic monomer to generate EOF. Furthermore, it is more convenient to change the direction and magnitude of EOF by changing the concentration of cationic or anionic surfactants in this system. An efficiency of monolithic capillary columns with more than 140000 plates per meter for neutral compounds has been obtained, and the relative standard deviations observed for to and retention factors of neutral solutes were about 0.22% and less than 0.56% for ten consecutive runs, respectively. Effects of mobile phase composition on the EOF of the column and the retention values of the neutral solutes were investigated. Simultaneous separation of basic, neutral and acidic compounds has been achieved.     

Separation of Hydroxybenzoic Acid Isomers by Capillary Zone Electrophoresis

Abstract

Capillary zone electrophoresis is a highly efficient analytical technique that has been shown to be particularly useful for the analysis of isomers. Using a cathodic injection and anodic detection scheme, ortho-, meta- and para-hydroxybenzoic acids were separated in a fused-silica capillary column with a phosphate buffer at pH 10.3 (25.0 mmol/1 phosphate + 0.20 mmol/1 cetyltrimethylammonium bromide (CTAB) + 10% (v/v) 1-propanol with an applied voltage of 10 KV followed by direct UV detection. The use of CTAB as electroosmotic flow modifier allows the rapid separation of the three isomers by reversing the direction of electro-osmotic flow. The influence of pH, CTAB concentration and organic solvents on the migration behaviour of the solutes were also studied.     

Dynamic coating of a capillary with room-temperature ionic liquids for the separation of amino acids and acid drugs by capillary electrophoresis

A room-temperature ionic liquid (IL), 1-ethyl-3-methyl-imidazolium tetrafluoroborate (1E-3MI-TFB), used for the coating of a silica capillary enables one to reduce or invert the electroosmotic flow (EOF) in capillary zone electrophoresis. Excellent separations of amino acids and ary lalkanoic acids were obtained. Such separations could not be obtained in a naked capillary in the presence of the cationic surfactants cetyltrimethylammonium bromide (CTAB) or polycationic polymer hexadimethrine bromide (HDB). The results indicate that 1E-3MI-TFB not only modulates the EOF but also acts as a discriminator. Further experiments indicate that the interaction between hydrogen at C-2 carbon of IL and acid drugs plays an important role in the separation. The text was submitted by the authors in English.     

聚合离子液体用作毛细管电泳背景电解质添加剂快速高效分离5种核苷类化合物

将聚乙烯基-3-乙基咪唑溴盐离子液体用作毛细管电泳背景电解质添加剂,利用聚合离子液体的阳离子聚合物性质静电吸附到毛细管内表面,成功实现电渗流的有效反转,建立了共电渗流模式下5种核苷类化合物分离的新方法。考察了聚合离子液体浓度、pH值等因素对电渗流的影响。在优化实验条件下,3.1 min内实现了对5种核苷类化合物的快速高效分离;将该方法分别与不加添加剂和加入离子液体单体后的体系进行对比,结果表明,该方法大大缩短了5种核苷类化合物的分析时间,提高了分析效率,最高柱效达95万/m塔板数,分析物的迁移时间RSD均不高于0.38%。该方法简单、快速、重复性好,具有很好的应用前景。