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。     

桥联β-环糊精液相色谱键合固定相研究

合成了两种桥联β-环糊精固定相,将其用于芳香烃位置异构体、氨基酸的对映异构体的拆分,同时比较了其与β-CD固定相的手性拆分效果。研究结果表明,桥联环糊精固定相对一些对映异构体具有较好的选择性;其对普通的环糊精固定相的选择性具有一定的补充或者改进作用。     

衍生化环糊精键合固定相色谱保留和手性识别机理的研究(Ⅱ)

合成了苯基氨基甲酸酯衍生化β-环糊精键合固定相CSP1和CSP2，在正相色谱条件下，一系列α-氨基膦酸酯化合物首次在这类衍生化β-环糊精固定相上实现了手性拆分。探索运用定量结构-对映异构体选择性保留关系的方法，将对映异构体的色谱保留和溶质子描述参数进行相关性联系建立定量方程，对比研究了该类苯基氨基甲酸酯生化β-环糊精键合固定相上可能的液相色谱保留和手性识别机理。     

衍生化环糊精键合固定相色谱保留和手性识别机理的研究（I）

合成了苯基氨基甲酸酯衍生化β－环糊精键合固定相,１４个α－氨基膦酸酯类化合物首次在该固定相和商品化的（Ｓ）－（＋）－萘乙基氨基甲酸酯衍生化β－环糊精固定相上进行液相色谱手性分拆。通过定量结构－对映异构体保留关系对比研究了两种不同的环糊精类固定相上可能的色谱保留和手性识别机理。     

以戊二醛为间隔臂的万古霉素键合手性固定相制备

基于戊二醛具有双官能团、高反应活性的特征,以其为间隔臂将万古霉素键合到氨基二氧化硅填料表面,制备了万古霉素键合手性固定相,制备方法简单易行。采用元素分析及扫描电子显微镜对制备的万古霉素键合手性固定相进行了表征。在高效液相色谱分离模式下,分别对谷氨酸、天冬氨酸、苯丙氨酸和异亮氨酸等4种手性氨基酸和手性药物罗格列酮进行拆分,其中谷氨酸和罗格列酮的分离度分别达到了2.0和2.3。系统考察了流动相条件对对映体拆分的影响,证实有机改性剂、缓冲液种类和浓度、pH值及温度对所测样品的保留行为和手性选择性均有显著影响。     

8—羟基喹啉衍生化β—环糊精键合硅胶液相色谱固定相的 …

β－环糊精键合硅胶经对甲苯磺酰化后,与８－羟基喹啉反应得到８－羟基喹啉衍生化β－环糊精键合硅胶固定相,采用元素分析,热分析及固体核磁波谱对键合相进行表征。考察了ＱＣＤＳ对位置异构体,丹磺酰化氨基酸异构体,苯丙酸类药物和核苷等的分离性能。     

流动相组成和温度对衍生化β-环糊精键合固定相拆分四种仲醇消旋体的影响

采用3,5-二甲苯基异氰酸酯衍生化β-环糊精键合固定相,以正己烷-脂肪醇为流动相,研究了脂肪醇结构及其浓度、柱温对2-苯基环己醇、2-萘基环己醇、4-三氟甲基-2-苯基环己醇以及3-(1-羟乙基)香豆素等四种仲醇手性拆分行为的影响.当流动相中醇的摩尔浓度相同时,异构体容量因子随脂肪醇碳链的增长而减小;柱温升高,异构体容量因子减小,而分离因子增大.用溶质的计量置换保留模型(SDM-R)和热力学理论对此现象进行了解释.     

衍生化环糊精键合固定相色谱保留和手性识别机理的研究(Ⅰ)

合成了苯基氨基甲酸酯衍生化β-环糊精键合固定相,14个α-氨基膦酸酯类化合物首次在该固定相和商品化的(S)-(+)-萘乙基氨基甲酸酯衍生化β-环糊精固定相上进行液相色谱手性拆分.通过定量结构-对映异构体保留关系对比研究了两种不同的环糊精类固定相上可能的色谱保留和手性识别机理.     

阳离子取代基对离子液体气相色谱固定相保留性能的影响

以双-三氟甲烷磺酰亚胺离子（［NTf₂］^-）、三氟甲基磺酸根离子（［TFO］^-）和六氟磷酸根离子（［PF₆］^-）为阴离子,合成了含有丙基、丁基、壬基、乙苯基或氰甲基等阳离子取代基的聚合乙烯基咪唑基离子液体固定相,制备了13种离子液体石英毛细管色谱柱。考察了离子液体固定相结构与色谱柱McReynolds常数、热稳定性和测试化合物保留行为之间的构效关系,研究了阳离子取代基对固定相保留性能的影响规律;同时考察了测试化合物保留指数随温度变化的规律。结果表明,所合成的离子液体固定相具有较强的极性,其保留性能不仅与阳离子取代基的性质密切相关,而且受取代基结构和阴离子影响明显;在考察的温度范围内,测试化合物的保留指数变化规律与传统色谱固定相完全相同。     

Correlation method for comparison of selectivity and retention on different chiral stationary phases

Summary The main chromatographic properties: selectivity and retention of two chiral stationary phases: (R)-3,5-dinitrobenzoylphenylglycine (CSP I) and (S)-3,5-dinitro-benzoylleucine (CSP II) have been compared on the basis of correlation of retention factors of derivatized esters of amino acids and derivatized aminoalcohols. The differences in retention and selectivity for the two CSPs can be easily estimated from the correlation equation. It is shown that in the case of the correlation for two sets of retention factors obtained on two different CSPs, it is mainly the intercept that decides which CSP has the better selectivity. It is demonstrated that the correlation method provides more informations on the selectivity and retention than comparison of the chromatographic data of single pairs of enantiomers. Additionally, the possible influence of the polar modifier mixed with n-hexane as diluent on the constants in the correlation equation is demonstrated.     

Some observations regarding different retention properties of HPLC stationary phases

Summary The retention of 32 monocyclic aromatic compounds and 14 polynuclear aromatic hydrocarbons (PAHs) has been studied on four different bonded phases in each of two mobile phases. An additional data set of 21 monocyclic aromatics judiciously chosen for their well-established solvatochromic parameters, 12 PAHs and 12 polychlorinated biphenyls (containing up to 10 chlorines), were studied on a single column. The results indicate that despite the accuracy of the solvatochromic linear solvation energy method for predicting and correlating the octanol/water partition coefficients and water solubilities of these environmentally important materials, the methodology is limited to only certain types of bonded phases. As a corollary to this observation, we caution others that the common practice of estimating log K_ow (K_ow=octanol-water partition coefficient) based on measurement of the reversed-phase capacity factors should be limited to specific types of columns. Part 5 of Solute-Solvent Interactions in Chemistry and Biology.     

Microcolumn liquid chromatography of polycyclic aromatic hydrocarbons and some isomeric compounds on cyclodextrin stationary phases

Preparative-grade bonded β- and γ-cyclodextrin stationary phases were used as the packing material of liquid chromato-graphic analytical microcolumns. Although the resulting columns are characterized by relatively low efficiency, the high selectivity of the cyclodextrin phases nevertheless allows their successful use for the separation of different classes of isomeric compounds that are difficult to resolve on conventional LC stationary phases. Examples of baseline (or almost baseline) separations of a number of isomeric compounds, including isomeric polycyclic aromatic hydrocarbons, are presented to demonstrate the analytical potential of such columns. Retention behavior of the separated isomers is discussed based on the structure of the solute molecule and the possibility of its inclusion into the molecular cavity of cyclodextrin stationary phases.     

Enantiomer separation by gas chromatography on cyclodextrin chiral stationary phases

Fused silica capillary columns coated with several alkyl or acyl cyclodextrin derivatives, especially those of α- and β-cyclodextrins, are suitable for the enantiomer separation of a wide variety of volatile compounds of different molecular size and functionality. Positional isomers and more than 250 pairs of optical isomers have been resolved, including chiral hydrocarbons, acetals, ethers, epoxides, carbonates, lactones, esters, acids, ketones, aldehydes, alcohols, halocarbons, and also nitrogen-and sulfur-containing compounds. The physical properties of the cyclodextrin derivatives, even those obtained as viscous fluids, could be improved by dissolving them in polysiloxane liquid phases commonly used for GLC.     

Prediction of HPLC retention times in gradient elution from isocratic data application to a set of non-homologous compounds and different stationary phases

Summary Polymethyloctylsiloxane-coated stationary phases have been prepared for liquid chromatography, by thermal reaction. The influence of the reaction conditions on retention and efficiency of test substances with different structures has been discussed. The materials have good stability in both acidic and basic eluents.     

Novel cyclodextrin chiral stationary phases for high performance liquid chromatography enantioseparation: Effect of cyclodextrin type

Three novel chiral stationary phases (CSPs) were prepared by regioselective chemical immobilization of mono(6^A-N-allylamino-6^A-deoxy)perphenylcarbamoylated (PICD) α-, β-, and γ-cyclodextrins (CDs) onto silica support via hydrosilylation. Their enantioseparation properties in high performance liquid chromatography (HPLC) were evaluated with a large spectrum of racemates including flavanone compounds, β-adrenergic blockers, amines and non-protolytic compounds. The effect of CD's cavity size on enantioseparation abilities was studied and discussed. The results indicated that CD's surface loading at silica support played an important role in the enantioseparation on these CSPs under normal-phase conditions while inclusion phenomena contributed the major driving force under reverse-phase conditions. As expected, α-PICD demonstrated the best resolutions towards flavonone and most aromatic alcohols under normal-phase conditions with the highest surface loading; while Fujimura's competitive inclusion model can be applied to explain the better enantioseparations towards β-adrenergic blockers, amines and non-protolytic compounds with α- and β-PICD CSPs. γ-PICD CSP showed superior enantioseparation ability for sterically encumbered analytes like flavanone compounds under both normal-phase and reversed phase conditions.     

Prediction of the net retention volumes in gas chromatography using porous polymers coated with different stationary phases

Summary A new expression which permits the prediction of the net retention volumes in gas chromatography with column packings of coated porous polymers is reported. The porous polymers Chromosorb 101 and Chromosorb 102 were used as supports and squalane, Ethofat and Carbowax 20M as stationary phases at three different column temperatures of 80°C, 100°C and 150°C. Several organic compounds of various polarity were used as test compounds and the net retention volumes, V_Ntheor, have been calculated according to this new expression. The V_Ntheor values were compared with the experimental net retention volumes, V_Nexp, and it was found that the difference between these two values is dependent on the type of compound and column packing. Nevertheless, the elution order could be predicted in most cases.     

Evaluation of novel dendrimer chiral stationary phases using HPLC

Summary The reversed phase chromatographic properties of the [G1]-L-glutamic and ethyl ester-AC-silica (1), [G2]-L-glutamic acid ethyl ester-AC-silica (2) and the [G1]-L-glutamic acidt-butyl ester-AC-silica (3) dendrimer stationary phases were evaluated. Initial studies involved the comparison between these phases with a classic reversed phase (i.e. ODS1) by the separation of a standard reversed phase test mixture composed of dimethylphthalate, nitrobenzene, anisole, diphenylamine and fluorene. Separations were achieved with comparable performance to those obtained with the conventional reversed phase (ODS1). However, it was apparent that the chromatographic selectivity exhibited by the dendrimer stationary phases was different from that of the ODS1 phase. On a per mole basis, the dendrimers exhibited similar (and sometimes greater) affinity for these analytes compared with the ODS1 ligand. Subsequent chromatographic experiments were conducted upon the dendrimer chiral stationary phases using chiral analytes under reversed phase and normal phase conditions. Chiral resolution was not observed.     

两种高热稳定性端羟基单阳离子型咪唑离子液体毛细管气相色谱固定相的性能评价

采用静态法将合成的端羟基单阳离子咪唑离子液体1-(6-羟己基)-3-丁基咪唑二(三氟甲基)磺酰亚胺盐(HHBIM-NTf₂)和1-(8-羟辛基)-3-丁基咪唑二(三氟甲基)磺酰亚胺盐(HOBIM-NTf₂)作为固定相制备离子液体毛细管气相色谱柱。采用Grob试剂、混合醇样品和芳香族异构体混合物对固定相色谱选择性进行了考察,Grob试剂和混合醇组分产生的尖锐、对称的色谱峰形及异构体混合物组分达到基线分离的结果均表明端羟基离子液体固定相具有良好的色谱选择性。HHBIM-NTf₂柱和HOBIM-NTf₂柱经250 ℃老化8 h后对异构体混合物的分离能力没有明显下降,而HHBIM-NTf₂柱经300 ℃老化后仍有理想的异构体选择性,表明端羟基离子液体固定相具有理想的热稳定性。本结果为进一步改善单阳离子型咪唑离子液体固定相的色谱性能提供了有效途径。