Experimental Study of Model Bonded Stationary Phases for Liquid Chromatography I. Silica/Polyethyleneoxide

Abstract

Model bonded phases have been prepared by reaction of polyethyleneoxide of various molecular weights (200 < M < 5.10⁶) on silica.

The retention behavior of solutes on these bonded stationary phases for liquid chromatography depends on silica loadings, grafted molecule length, solute size and solvent nature. Different mechanisms such as dissolution effect in the grafted phase, adsorption on mineral support and steric exclusion due to the residual porosity of silica, are involved in the observed separations. An expression of elution volumes in relation with these mechanisms is proposed.

Chromatographic data and thermodynamic predictions are in good agreement.     

高效液相色谱环糊精键合固定相

环糊精是由Ｄ（＋）－葡萄糖单元通过α－１，４糖苷键连接的环状齐聚糖，其最典型的性质是能与许多客体分子形成包容配合物。高效液相色谱环糊精键合固定相广泛用于对映异构体，非对映异构体，结构异构体和常规化合物的分离。     

高效液相色谱烷基硅胶键合固定相

综述了高效液相色谱烷基硅胶键合固定相研究的最新进展,参考文献４０篇。     

硅胶基质高效液相色谱填料研究进展

高效液相色谱(HPLC)不仅是一种有效的分析分离手段,也是一种重要的高效制备分离技术。色谱柱是HPLC系统的核心,不同性能的填料是HPLC广泛应用的基础。硅胶是开发最早、研究最为深入、应用最为广泛的HPLC固定相基质,其制备方法主要有喷雾干燥法、溶胶-凝胶法、聚合诱导胶体凝聚法及模板法等。近年来,亚2μm小粒径硅胶、核-壳型硅胶、双孔径硅胶、介孔性硅胶、有机杂化硅胶等新型硅胶应用于HPLC并取得了色谱分离技术的飞速发展,例如基于亚2μm填料的超高压液相色谱技术、基于核-壳型填料的快速分离技术、基于杂化硅胶填料的高温液相色谱技术等。硅胶经表面化学键合、聚合物包覆等有机改性可制得先进的大分子限进填料、温敏性填料、手性填料等,大大扩展了HPLC的应用范围。本文对液相色谱用硅胶的制备方法、改性与修饰方法以及硅胶基质固定相的评价方法加以系统综述,概述了新型硅胶在HPLC中的应用进展,并对硅胶基质填料的发展方向与应用前景进行了展望。     

聚苯乙烯包夹硅基高效液相色谱固定相的研究

用包夹聚合法制备出一种新型的聚苯乙烯包夹硅基高效液相色谱固定相并进行了固定相的表征。对色谱行为的研究表明此固定相在分离碱性、强极性溶质时有良好的分离性能,固定相在较高ｐＨ的洗脱液中有较好的稳定性。     

Application of Native and Hydroxypropyl-Substituted β-Cyclodextrin Bonded Silica Gel as Stationary Phases for High Performance Liquid Chromatography

Two chiral stationary phases for high-performance liquid chromatography (HPLC) have been synthesized by grafting native and 2-hydroxypropyl-β-cyclodextrin onto silica gel by a previously described method. They were tested under reversed-phase conditions. These two materials enable separation of the enantiomers of a variety of drugs (benzodiazepine anxiolytics, arylpropionic acids, anti-inflammatory and anticoagulant agents) and herbicides (aryloxyphenoxypropionic esters). Both chiral stationary phases enabled good chiral recognition in reversed-phase mode. The effects of the nature and composition of the mobile phase, of compound structure (mechanisms of chiral discrimination), and of flow-rate were studied.     

Precursor Carboxy-silica for Functionalization With Interactive Ligands. II. Carbodiimide Assisted Preparation of Silica Bonded Stationary Phases with D-glucamine for Hydrophilic Interaction Liquid Chromatography

Chromatographia - A precursor carboxy-silica support was introduced for grafting a retentive polar ligand, namely D-glucamine, for use in hydrophilic interaction liquid chromatography. This support...     

硅胶基质高效液相色谱固定相

结合作者实验室的研究工作,并引用文献157篇,对高效液相色谱用硅胶基质色谱填料进行了综述。     

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.     

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.

     

亲水作用色谱填料的研究进展

亲水作用色谱是一种新型的色谱分离模式.此类色谱模式集反相色谱的经济廉价与正相色谱的优点于一体,有效补充了反相色谱的不足.简单介绍实验室中合成的新型亲水色谱固定相.     

The Evolution of Chiral Stationary Phases for Liquid Chromatography

The development of effective chiral stationary phases (CSPs) and separation strategies for the liquid chromatographic (LC) resolution of enantiomers has been beneficial to many scientific disciplines. Over the last decade the number and type of CSPs has expanded tremendously. Not only have new classes of chiral selectors been introduced, but also many of the first CSPs have been changed and/or improved. The second or third generation of a CSP often can be different from the original. This can be confusing and intimidating to someone just entering the area of LC enantiomeric separations. Fortunately, all CSPs can be categorized in one or another of a few classes. There are generally one or two columns that can accomplish the majority of separations in each class. In this work we look at the different classes of CSPs and how they have expanded and changed over the last decade.     

Separations in Thin Layer and High Performance Liquid Chromatography Using Alkyl Silica Gel Bonded Phases

Abstract

Separations in thin layer (TLC) and high performance liquid chromatography (HPLC) using alkyl bonded phases were carried out under optimum solvent conditions for each of three phases, RP-2, RP-8 and RP-18. The phases were tested for their efficiency and resolving power using three groups of compounds in three binary organic-water mobile phases. The organic solvents were acetonitrile, methanol and tetrahydrofuran, which are widely used as solvent modifiers in reversed phase liquid chromatography.

The results showed that, unlike HPLC, TLC using RP-18 plates was the most, and RP-2 plates the least, efficient. A naphthalene and biphenyl mixture which was resolved by HPLC using any of the three solvents and columns was not resolved by TLC using any plate or solvent combination, unless the plate was prewashed with an organic modifier. The addition of NaCl (1–2% wt/vol) to the solvent for TLC speeded development unless an alcohol was used, but did not greatly affect the separation.     

用液体有机硝酸盐作气相色谱固定相

选用二乙胺、三乙胺、正丙胺、异丙胺、正丁胺和异丁胺的硝酸盐作为气相色谱固定相,测得它们的使用温度范围均超过１００℃。上述液体有机盐对具有大偶极矩分子化合物或具有氢键成键能力的化合物（如醇类）有良好的选择性,特别对醇类异构体的分离效果更佳;对酮类及单官能团取代苯的分离效果更令人满意,但对烃类不适用。     

十四烷基胺键合固定相的反相色谱性能

制备了一种新型反相液相色谱固定相──十四烷基胺硅胶键合固定相。以甲醇和水为二元流动相,评价了该固定相的疏水性、选择性和残留硅醇基活性。同时分离了包括碱性、酸性和中性有机化合物在内的混合物。结果表明,在该固定相上,碱性化合物的色谱峰对称性较好,硅酸基活性受到抑制,并具有良好的选择性。     

Preparation and Evaluation of Calix[8]arene Bonded Silica Stationary Phase for High Performance Liquid Chromatography

In recent years, calix[n]arenes (n=4,5,6,7,8) as stationary phase have been introduced into the field of chromatography. In our previous works, we have synthesized, characterized and evaluated two different silica-bonded calix[n]arenes (n=4,6) stationary phase, on which the chromatographic behavior of PAHs, positional isomers,nucleosides and bases was investigated. In this paper we report the preparation of calix[8]arene bonded silica stationary phase, and characterization of its structure and chromatographic behavior.     

H PLC聚合物手性固定相

对近年来文献报道的高效液相色谱聚合物手性固定相及其在手性拆分中的应用予以综述 ,并阐述了聚合物手性固定相拆分机理的研究进展。     

Electrochemically Controlled Liquid Chromatography on Conducting Polymer Stationary Phases

Abstract

Electrochemically controlled high performance liquid chromatography (EC/HPLC) using a conducting polymer stationary phase, has been investigated in the present paper. Polypyrrole coated reticulated vitreous carbon (RVC) particles have been employed as the stationary phase. Chromatographic characterization has been carried out using various molecular probes. The results indicate that chromatographic retention can be altered by the imposition of small electrical potentials on the stationary phase and that such effects can be used to improve the separation of certain compounds.