Preparative Liquid Chromatographic Separation of Amino Acids and Peptides on Amberlite XAD-4

Abstract

Amberlite XAD-4, a polystyrene-divinylbenzene copolymic reversed phase adsorbent which has a 750 m²/g surface area and 50Å porosity, was used as the stationary phase for the preparative liquid chromatographic separation of amino acids and peptides. Mixtures of > 40 mg and > 100 mg sample load were separated on 8.0 and 20.5 mm i.d. columns, respectively. Mixed solvent and acidic and basic solutions which cannot be used with silica and alkyl-modified silica, were evaluated as mobile phases. Mixtures of amino acids, diastereomeric di-and tri-peptides, diastereomeric dipeptides obtained from the reaction of tert-butyloxycarbonyl-L-amino acid-N-hydroxysuccinimide esters with D, L-amino acids, and enkephalin peptides were separated. Major and minor sample components were isolated.     

新型侧链聚硅氧烷高分子液晶作毛细管柱气相色谱固定液的研究

 以合成的新型胆甾酯类侧链聚硅氧烷高分子液晶作固定液 ,涂渍在弹性石英毛细管柱上 ,获得了具有较高的柱效和选择性、良好的热稳定性、适于分离多种异构体混合物的毛细管柱。     

锥型与圆柱型液相色谱制备柱的比较研究

用可视化柱上图形分析对入口内径大于出口内径的锥型液相色谱制备柱的样品谱带流型进行了研究。在一定的实验条件下，锥型柱与圆柱型柱的流动相流型曲线相反。对与锥型柱有相同长度、相同容积的圆柱型色谱柱的柱效、样品容量及峰高的比较研究表明：锥型柱优于圆柱型柱。锥型柱的样品容量约为圆柱型柱的2倍，柱效比圆柱型的高36％，色谱流出曲线峰值高于圆柱型柱12％。     

高效液相色谱中的纤维素衍生物手性固定相

本文评述了高效液相色谱中的纤维素衍生物手性固定相，介绍了纤维素衍物生的主要类型，阐述了纤维素省生物手性固定相的光学拆分机理，并评述了该手性固定相在医药品、生化和有机中间体的分析及对映体制备等方面的应用。引文６４篇。     

表面分子印迹聚合物纳米线用于蛋白质的特异性识别

手性配体交换色谱是拆分手性化合物,特别是氨基酸和羟基酸对映体的一种有效方法,通常以光活性氨基酸或其衍生物为手性选择子,可通过键合及涂渍制备手性固定相,也可作为流动相添加剂来实现手性配体交换色谱分离分析,配体交换键合固定相需要完成载体和手性选择子之间的偶联,键合量因受到载体和制备条件的影响而较难控制,且柱效较低。     

聚硅氧烷键合的离子液体用作高温气相色谱固定相的研究

合成了阴离子为二(三氟甲基磺酸酰)亚胺(NTf-2)的新型聚硅氧烷键合离子液体 ([PSOMIm][NTf2]),并采用静态涂渍法,制备了毛细管气相色谱柱.该固定相具有良好的热稳定性.热重测试显示,温度高于380 ℃后,[PSOMIm][NTf2]开始缓慢分解.色谱性能评价显示,此固定相对多种异构体和同系物均具有良好的分离选择性和高的热稳定性.对Grob试剂的分离结果表明,各种组分均能在柱上得到良好的分离且峰的对称性很好.此新型聚合物离子液体在高温气相色谱固定相的研究和应用方面具有较大的潜力.     

Crystalline Degradation Products of Vancomycin as a New Chiral Stationary Phase for Liquid Chromatography

Two crystalline degradation products (CDP-1-M and CDP-1-m) are formed from vancomycin by hydrolytic loss of ammonia. The CDP are structurally similar to vancomycin, with two carboxyl groups, but are biologically inactive. In this work the CDP of vancomycin have been covalently linked to silica gel and their ability to resolve racemic mixtures, their stability, and their loading has been evaluated by HPLC. Elemental analysis and scanning electron microscopy were used to monitor the surface of this new stationary phase. Enantiomeric separation was achieved for some compounds that have not been previously been separated on other chiral stationary phases.     

离子液体改性的气相色谱固定相研究

合成了哑铃型离子液体, 并将FFAP与其按2∶1的质量比混合涂渍交联在石英管内壁, 柱效为3500 p/m, 极性为435.2, 比FFAP柱的极性明显降低. 但由混配的固定相制成的色谱柱对极性和弱极性物质的选择性都优于FFAP柱. 此外, 该固定相对芳香位置异构体、羧酸、烷烃、醇类、酯类及多环芳烃混合物等均具有较好的分离选择性.     

聚硅氧烷键合离子液体的合成及色谱性能

提出了一种基于聚硅氧烷键合离子液体(PSOIL)的气相色谱固定相的方法, 即首先合成γ-氯丙基聚硅氧烷, 然后通过氯丙基与甲基咪唑的反应合成了聚硅氧烷负载的离子液体, 并对其色谱性能及分离选择性进行了评价.     

高效制备液相色谱柱技术的研究进展

本文概述了高效制备液相色谱柱的柱型结构、填料以及柱填充方法等研究的最新进展,讨论了制备柱与分析柱的不同特征,对目前普遍使用的压缩型制备柱的类型、结构及填充方法作了较为全面的评述,总结比较了工业化制备色谱填料不同于分析色谱填料的特点,探讨了高效制备液相色谱柱技术的应用和发展前景.     

新型侧链聚硅氧烷液晶高分子用作毛细管柱气相色谱固定液

1 引 言寻求高选择性固定液是当今毛细管柱气相色谱研究的重要课题之一。1982年,Finkelmann等首次把侧链聚硅氧烷高分子液晶用作气相色谱固定液,成功地分离了二环芳烃异构体2,3－二甲萘、1,4－二甲萘和二苯甲烷。侧链聚硅氧烷高分子液晶易涂渍,选择性和热稳定性皆优于低分子液晶。本文对两种新型侧链聚硅氧烷液晶高分子用作气相色谱固定液进行了探讨。2 实验部分2.1 仪器与试剂 SP－3400气相色谱仪(北京分析仪器厂),氢火焰离子化检测器（FID）。蒽、菲、芴混合物（溶剂二氯甲烷),邻、间、对二甲苯混合物,二甲酚异构体混合物（溶剂…     

Determination of Benzodiazepines in Serum by High Performance Liquid Chromatography Using Radially Compressed Columns and an Aqueous Methanolic Mobile Phase

Abstract

Diazepam, oxazepam and N-desmethyldiazepam are determined by high performance liquid chromatography using a radially compressed C18 column and an aqueous methanolic mobile phase. The chromatographic separation is completed within 10 minutes. The drugs are recovered from serum by extraction with hexane:ethyl acetate 70:30, v/v.

The method is linear in the range 50-1600 ng/ml for all the drugs, Coefficients of variation are less than 6.2% for two studied concentration levels.     

Liquid Crystals as Stationary Phases in Chromatography

The most correct analysis of the compositions of diverse analytes mixtures is significant for analytical studies in different fields; however, many prevalent analytes cannot be identified employing traditional partition gas chromatographic methods. Thus, the increasing requirements on analytes of isomeric compounds and the problems encountered in their separation demand a study of more diverse analytical systems which are characterised by higher selectivity. Therefore, the selectivity and polarities of various liquid crystals (rod-like, banana-shape, biforked, oxygen, sulphur, nitrogen, and metal containing molecules, Schiff-base, and polymeric dendrimers) employed as liquid crystalline stationary phases (LCSPs) have been discussed from both points of views, namely, their analytical applications and thermodynamic characteristics of infinitely diluted probes with different acceptor–donor properties. Extreme particular effort has been paid to the different interdependencies between the bound up chemical structures of liquid crystal molecules with their different acceptor–donor properties and the connected resolution capabilities in the interpretation of the probe—LCSP systems, on the basis of the \( { \ln }V_{g\left( T \right)} = f\left( {\frac{1}{T}} \right) \) and \( { \ln }\left( {\frac{{a_{1} }}{{w_{1} }}} \right)^{\infty } = f\left( {\frac{1}{T}} \right) \) dependencies, with regard to the LCSP compositions, which have been controlled by the counterbalancing of the enthalpy and entropy factors. The properties of binary systems composed of liquid crystalline poly(propyleneimine) dendrimers—rod-like molecules of liquid crystals and effects of the dendrimer structure, the chemical nature, and molecular size of the non-mesogens on the ability to dissolve in the liquid crystalline phases, have been interpreted. Practical applications of metallomesogenes and chiral stationary phases for analytical separation of different organic substances have also been taken into consideration.

     

高效液相色谱中的纤维素衍生物手性固定相

评述了高效液相色谱中纤维素衍生物手性固定相直接拆分对映体的进展，介绍了纤维素衍生物的主要类型，纤维素衍生物作手性固定相三种不同方式的特点以及新的纤维素衍生物手性固定相应用，并结合色谱，NMR和分子模型设计和理论计算等方法讨论了纤维素衍生物手性固定的拆分机理。     

高效液相色谱蛋白质手性固定相

本文综述了近年文献中已报道的各种高效液相色谱蛋白质（酶）手性固定相及其在手性拆分中的应用，并阐述了蛋白质作为手性选择剂拆分机理的研究进展。     

新型高效液相色谱固定相—咪唑键合相的研究

本文报道一种新型咪唑键合相的制备,并将这种键合相同氨基键合相(YWG-NH_2)的正相色谱性质进行比较,结果表明:咪唑键合相对于分离多环芳烃异构体具有更高的色谱选择性。另外,由于咪唑分子的络合特性和在固定相表面形成螯合物结构,咪唑键合相对Cu(Ⅱ)有更强的络合能力。咪唑-Cu(Ⅱ)键合相可用于高效配体交换色谱中解决芳胺异构体及其类似物的分离。     

Liquid Crystals as Stationary Phases for High Performance Liquid Chromatography

Abstract

Liquid crystals have not yet been used as stationary phases in High Performance Liquid Chromatography. This is surprising since Gas Chromatography has demonstrated some remarkable separations, many of which are not possible with normal stationary phases, that have been achieved where liquid crystals have been employed as the stationary phase. The objective of the work reported here was to evaluate the chromatographic properties of several cholesteric liquid crystals as stationary phases in HPLC. Included in this study was an investigation of the feasibility of bonding a cholesteric moiety to a solid support for use in HPLC. The columns showed a dramatic increase in capacity factor for steroid molecules as the temperature of the column was increased.     

咪唑键合硅胶液相色谱固定相的正相色谱行为

该文将咪唑键合硅胶液相色谱固定相填充到毛细管中,在自制的微柱液相色谱系统下以碱性(胺类)和酸性(酚类)化合物为溶质对该固定相的正相色谱行为进行考察.结果表明该键合相在正相色谱模式下对碱性化合物具有良好的分离选择性,而酸性化合物在流动相中加入改性剂乙酸的条件下也实现了较好的分离.研究表明,正相模式下该键合相的保留机理存在着氢键、静电吸引及π-π等相互作用机制.