全甲基化2,3,6—三—（O—2‘—羟丙基）—β—环糊精固定液热力学性质和分 …

将合成的全甲基化２，３，６－三（Ｏ－２‘－羟丙基）β－环糊精（ＰＭＨＰ－β－ＣＤ）固定液直接涂渍在弹性石英毛细管柱内壁，１４组对映异构体、６组芳香族益异构体化合物等在该柱上得到满意分离。通过测定以上化合物在该柱上的热力学参数：焓、熵、自由能及焓变差、熵变差、探讨了固定液对所测化合物的分子识别和色谱分离机理。结果表明，芳香族化全哦的△Ｓ－值在ＰＭＨＰ－β－ＣＤ高２０－３０Ｊ／ｍｏｌ．Ｋ，构型效应明显     

全甲基化2,3,6-三-(O-2’-羟丙基)β-环糊精固定液热力学性质和分离机理

将合成的全甲基化２，３，６－三（Ｏ－２’－羟丙基）β－环糊精（ＰＭＨＰ－β－ＣＤ）固定液直接涂渍 在弹性石英毛细管柱内壁，１４组对映异构体、６组芳香族位置异构体化合物等在该柱上得到 满意分离。通过测定以上化合物在该柱上的热力学参数：焓、熵、自由能及焓变差、熵变差，探 讨了固定液对所测化合物的分子识别和色谱分离机理。结果表明，芳香族化合物的－△Ｓ值在 ＰＭＨＰ－β－ＣＤ柱上比 ＴＢ－β－ＣＤ高２０～３０ Ｊ／ｍｏｌ·Ｋ，构型效应明显，极性选择性也比后者高。     

芳香族化合物在苯并系列冠醚聚硅氧烷固定液上的保留机理

分离测得了不同结构芳香族化合物在单苯并（ＰＳＯ－Ｂ－３－１５Ｃ５或１８Ｃ６）、双苯并（ＰＳＯ－ＤＢ－３－１５Ｃ５）和双苯并双叔丁基（ＰＳＯ－ＤＴＢ－３－１５Ｃ５）取代的１５Ｃ５聚硅氧烷固定液上的保留指数、相对保留值以及１０组异构体的热力学参数──溶解焓△Ｈｓ,溶解摘△Ｓｓ和自由能△Ｇ;研究探讨了冠醚环上不同苯基取代的固定液结构对芳香族位置异构体保留行为的影响;通过热力学参数对不同冠醚柱子选择性的表征,证明了苯并系列冠醚固定液对芳烃位置异构体的良好选择分离,主要取决于冠醚环腔的高电子云密度所产生的定向力和强诱导力以及分子和冠醚环腔的适应程度,特别是空间位阻效应起了重要作用。     

冠醚苯酚共缩聚物的合成与性能

由２，６－二羟甲基－４－甲基（或磺酸基）苯酚分别和芳香族冠醚（Ｂ１５Ｃ５、Ｂ１８Ｃ６、ＤＢ１８Ｃ６、ＤＢ２４ｃ８等）在强酸催化剂下缩聚，合成了２个系列冠醚共缩聚物。它们的萃取能力和配合作用均优于相应的单冠醚，并可作为树脂吸附分离多种金属离子，作为配合剂测定钾、钠以及作为气相色谱固定液分离多种有机物。     

套索冠醚固定相的气相色谱研究

用一种新合成的套索冠醚Ｎ，Ｎ′－双（乙酰苄胺）－二氮杂－１８－冠－６作为固定相，涂渍在弹性石英毛细管内，测其柱效、惰性、热稳定性、平均极性及选择性等性质。实验表明，它具有良好的色谱性能，中等极性，分离选择性高，适用于对醇、卤代烃、芳香烃等各类异构体的分离，并从分子结构和热力学参数等探讨了保留机理。     

全丁基-β-环糊精与硝酸银的混合液作为毛细管气相色谱固定相的研究

 将合成的全丁基-β-环糊精+硝酸银(聚乙二醇400作溶剂)混合固定液静态涂渍在弹性石英毛细管柱内壁,7组对映异构体、4组芳香族位置异构体化合物等在该柱上得到满意分离。通过测定以上化合物在该柱及全丁基-β-环糊精柱上的热力学参数(焓、熵、自由能及焓变差、熵变差),探讨了固定液对所测化合物的色谱分离机理。结果表明,混合固定液对所测化合物具有协同效应     

环糊精-冠醚用作毛细管气相色谱手性固定相的研究

合成了一种新型的气相色谱固定相６－（１－苯并氮杂－１５－冠－５）－２,３,６－Ｏ－全甲基－β－环糊精,并用于一些对映体与芳香族位置异构体的分离。结果表明,新型固定相具有良好的选择性和拆分能力,显示了环糊精与冠醚对化合物分离的协同作用。     

侧链长短对全氧冠醚聚硅氧烷色谱性能的影响

设计合成了一种新型聚硅氧烷侧链全氧冠醚（丙烷氧甲基１５－冠－５），将其涂渍在示经处理的弹性石英毛细管柱上，其色谱柱具有高柱效，较宽的使用温度范围，高热稳定性和优异的选择性。并且通过与另一种氧烷侧链冠醚固定液涂渍柱的比较，考察了侧链脂肪间隔基的长短对冠醚固定液色谱性能的影响。研究了固定液对样品的分离机理。     

冠醚化合物在色谱中的应用新进展

本文简要介绍了近年来冠醚化合物,特别是带有手性的冠醚化合物及聚硅氧烷冠醚固定液在气液相色谱中的应用发展。并对气相色谱分离机理进行了探讨。     

双苯甲酰胺冠醚固定相的合成及毛细管柱气相色谱性能…

合成了一种新型的双苯甲酰胺冠醚固定相：（１Ｓ，２Ｓ）－１－（对苯甲酰胺基）苯基－２－苯甲酰胺基－１６－冠－５，其结构经红外光 谱、核磁共振、质谱及元素分析数据证实这种固定相的柱交、热稳定性、极性及选择性等色谱特性。该类固定相对极性位置异构分离效果良好。由于冠醚上引入苯甲酰胺取代基，因而对苯胺类及不经衍生化 碱性化合物能特殊选择性地分离。     

氮杂冠醚聚硅氧烷固定液的色谱保留机理

氨杂冠醚聚硅氧烷是一类呈中等极性的新颖气相色谱固定液．本文通过测定醇、酯、卤代烃和苯系列化合物的色谱保留值和相应势力学参数，研究它对上述不同化合物的保留机理及其分子识别的热力学性质     

套索冠醚毛细管色谱柱的研制

用套索冠醚N,N′-双(2-甲基吡啶)-二氮杂-18-冠-6作为固定相,涂渍在弹性石英毛细管内,测其柱效、惰性、热稳定性、平均极性及选择性等性质.其结构由元素分析、红外光谱、核磁共振及质谱分析的试验数据所证实.试验表明,它具有良好的色谱性能、中等极性,适用于对醇、卤代烃、芳香烃等各类异构体的分离,并用分子结构观点探讨了保留机理.     

Chromatographic retention and thermodynamics of the adsorption of α-phenylcarboxylic acid enantiomers on a chiral stationary phase with a grafted antibiotic eremomycin: Effect of eluent pH

The effect of the pH of aqueous–ethanol mobile phases on the retention and adsorption thermodynamics of the optical isomers of several α-phenylcarboxylic acids on a chiral stationary phase “Nautilus-E” with a grafted antibiotic, eremomycin, was studied. It was determined that ionic interactions dominated in the retention of α-phenylcarboxylic acid enantiomers. It was revealed that the Nautilus-E adsorbent was most selective to acids, the adsorption of which is an enthalpy-controlled process. It was found that the nature of adsorption was changed by varying the eluent pH. The dissociation constants of α-phenylcarboxylic acids have been determined by chromatographic method in aqueous–ethanol solution. A statistical analysis of the phenomenon of enthalpy-entropy compensation was performed, and a manifestation of the false compensation effect was established. It was shown that the spatial configuration of the molecule and the presence of polar groups on a chiral carbon atom in its structure have a greater influence on the chiral recognition mechanism of acid enantiomers using the Nautilus-E CSP.     

新型苯基桥键色谱固定相的热力学性质

将制备的球形苯基桥键型杂化介孔色谱固定相与商品化的C18和苯基键合硅胶固定相对比,研究其热力学性质。以稠环芳烃为例,探讨了溶质在固定相和流动相之间的迁移焓变、迁移熵变等热力学参数的变化。结果表明,与两种商品化的固定相不同,实验制备的苯基桥键固定相不存在明显的焓-熵补偿效应,证实新型桥键固定相分离机理是疏水作用、π-π作用、包结作用等协同作用的结果。     

Application of bromoacetate‐substituted β‐CD‐bonded silica particles as chiral stationary phase for HPLC

Bromoacetate‐substituted [3‐(2‐O‐β‐cyclodextrin)‐2‐hydroxypropoxy]propylsilyl‐appended silica particles (BACD‐HPS), an important and useful synthetic intermediate for preparation of novel types of macrocycles‐capped β‐CD‐bonded silica particles including crown ether/cyclam/calix[4]arene‐capped β‐CD‐bonded silica particles, have been prepared and used as chiral stationary phase for HPLC. This synthetic stationary phase is characterized by means of elemental analysis. For the first time, the chromatographic behavior of BACD‐HPS was systematically evaluated with several disubstituted benzenes and some chiral drug compounds under both normal and RP conditions in HPLC. The results show that BACD‐HPS has excellent selectivity for the separation of aromatic positional isomers and chiral isomers of some drug compounds when used as stationary phase in HPLC.     

Investigation of the chromatographic regulation properties of benzyl groups attached to bridging nitrogen atoms in a calixtriazine‐bonded stationary phase

Two reversed‐phase/anion‐exchange mixed‐mode stationary phases for high‐performance liquid chromatography using calixtriazines as chromatographic ligands were investigated with Tanaka test solutes, monosubstituted benzenes, aromatic positional isomers, and inorganic anions. Calixtriazine as a chromatographic ligand has been reported previously, but the benzylated nitrogen‐bridged calixtriazine‐bonded silica gel reported in this study is new. The experimental data showed that the calixtriazine platform is a unique chromatographic selector because its multiple active sites are available for different solutes and its chromatographic selectivity could be tuned by introducing substituent on the bridging nitrogen atoms present in the calixtriazine matrix. The synergistic effects of aromatic rings, nitrogen atoms, benzyl groups, and tunable cavity in the host molecule influenced the separation selectivity by multiple retention mechanisms. Such hybrid stationary phases provide more versatility and have great potential in the analysis of complex samples. Moreover, the synthetic protocols presented herein may provide an alternative understanding on macrocyclic host–guest chemistry, leading to new and selective separation media.     

Preparation and characterization of a magnesia-zirconia stationary phase modified with β-cyclodextrin for reversed-phase high-performance liquid chromatography

A new stationary phase of magnesia-zirconia composite matrix for high-performance liquid chromatography was first prepared by modification of β-cyclodextrin (β-CD) via fosfomycin as a spacer. Various modification procedures were attempted for achievement of successful modification. The modified composite was characterized by using coloration, elemental analysis, diffused reflectance FT-IR, surface area and pore size distribution. The separation of alkylbenzenes, polycyclic aromatic hydrocarbons, positional isomers of some acidic, basic and amphoteric disubstituted benzenes was studied on the new stationary phase. The effect of pH and methanol content in the mobile phase on retention and separation selectivity for the positional isomers were investigated. The chromatographic performance of CD modified magnesia-zirconia was compared with fosfomycin modified magnesia-zirconia as intermediate material and bare magnesia-zirconia as raw material. The results show that various retention mechanisms such as hydrophobicity, inclusion complexation and hydrogen bond interaction exist in the chromatography process of the packing modified with CD. The β-CD played the major role in the chromatographic property of this new stationary phase. The modified magnesia-zirconia exhibits superiority of separation for basic aromatics and high stability above pH 11.     

Retention mechanism of poly(ethylene oxide) in reversed-phase and normal-phase liquid chromatography

The retention behavior of low- and high-molecular-mass poly(ethylene oxide) (PEO) in reversed-phase (RP) and normal-phase (NP) liquid chromatography was investigated. In RPLC using a C18 bonded silica stationary phase and an acetonitrile-water mixture mobile phase, the sorption process of PEO to the stationary phase showed deltaH(o) > 0 and deltaS(o) > 0. Therefore, PEO retention in RPLC separation is an energetically unfavorable, entropy-driven process, which results in an increase of PEO retention as the temperature increases. In addition, at the enthalpy-entropy compensation point the elution volume of PEO was very different from the column void volume. These observations are quite different from the RPLC retention behavior of many organic polymers. The peculiar retention behavior of PEO in RPLC separation can be understood in terms of the hydrophobic interaction of this class of typical amphiphilic compounds with the non-polar stationary phase, on the one hand, and with the aqueous mobile phase, on the other. The entropy gain due to the release of the solvated water molecules from the PEO chain and the stationary phase is believed to be responsible for the entropy-driven separation process. On the other hand, in NPLC using an amino-bonded silica stationary phase and an acetonitrile-water mixture mobile phase, PEO showed normal enthalpy-driven retention behavior: deltaH(o) < 0 and deltaS(o) < 0, with the retention decreasing with increasing temperature and PEO eluting near the column void volume at the enthalpy-entropy compensation point. Therefore, high-resolution temperature gradient NPLC separation of high-molecular-mass PEO samples can be achieved with relative ease. The molecular mass distribution of high-molecular-mass PEO was found to be much narrower than that measured by size-exclusion chromatography.     

杯[4]芳烃衍生物气相色谱固定相分离芳烃异构体的热力学/超热力学研究

用热力学／超热力学方法对杯[4]芳烃衍生物气相色谱固定相上芳烃位置异构体的分离进行了研究。考察了一系列芳烃位置异构体在杯芳色谱柱上分离过程的热力学参数及其选择性之间的关系,并对杯[4]芳烃衍生物气相色 谱固定相分离芳烃位置异构体的保留机理进行了探讨。     

One-pot synthesis of pillar[5]quinone-amine polymer coated silica as stationary phase for high-performance liquid chromatography

To expand the application of pillararene in chromatographic separation, we designed and fabricated a pillar[5]quinone-amine polymer coated silica through quinone-amine reaction by facile one-pot synthesis method, which was applied as a stationary phase for high-performance liquid chromatography. Separation of hydrophobic compounds, hydrophilic compounds, halogenated aromatic compounds, and 11 aromatic positional isomers was achieved successfully in this stationary phase. Reverse-phase separation mode and hydrophilic-interaction separation mode were proved to exist, indicating the potential application of the mix-mode stationary phase. Studies of chromatographic retention behavior and molecular simulation showed that multiple interactions might play an important role in the separation process, including hydrophobic interaction, hydrogen-bonding interaction, aromatic π-π interaction, electron donor-acceptor interaction, and host-guest interaction. Column repeatability and stability were tested, which showed relative standard deviations of retention time less than 0.2% for continuous 11 injections, and the durability relative standard deviations of retention time were less than 0.91% after 90 days. This novel design strategy would broaden the application of pillararene-based covalent organic polymer in chromatography and separation science.