Retention Behaviour of Higher Fluorinated Polycyclic Aromatic Hydrocarbons in Reversed-Phase Liquid Chromatography

The retention behaviour of 18 di-, tri- and tetra-fluorinated phenanthrenes, chrysenes and benzo[g]chrysenes in column liquid chromatography was studied for a monomeric and a polymeric octadecyl-bonded silica phase. The retention times were much longer than those of the parent compounds and strongly dependent on the F-substitution pattern. The influence of geometric factors like calculated length-to-breadth ratios (LB ratios) and planarity, and electronic factors such as dipole moment and London forces was investigated. A linear correlation was found between the dipole moment and/or the degree of fluorination and the retention factor for the monomeric phase, and additionally between the maximum LB ratio and the retention factor for the polymeric phase. These findings are interpreted using the models of partition and the slot-model, respectively. Polyfluorinated polycyclic aromatic hydrocarbons are not very similar to parent PAHs and are, therefore, less suitable as internal standards in PAH analysis than the monofluorinated analogues especially in cases when the similarity of physico-chemical properties is critical.     

氨基苯磺酸和氨基萘磺酸在反相色谱中的保留行为

本文考察了冲洗剂中强组分浓度、无机盐浓度和酸度对保留值的影响,结果表明在溶质的 lnk 与 C_b 间线性关系中不能包括 C_b=0时的实验点。同时还观察到线性回归的 a 值与C_b=0时实测的 lnk′值存在较好的线性关系,酸度对 k′值的影响较复杂;溶质的保留值随无机盐浓度的增加而增大。     

Separation of the Geometric Isomers of 4-Octyl-1,1a,2,3,4,5,6,6a-Octahydro-Cyclopropa[f]Indene-1-Carboxylic Acid Ethyl Ester and their Positional Isomers by Reversed-Phase HPLC

A high-performance liquid chromatography (HPLC) method for the separation of geometric and positional isomers is described. A gas chromatography-mass spectrometry (GC-MS) method for the detection and evaluation of various isomers is described. The developed method was able to separate the isomers in the purity range of 97.96% to 99.3% (GC analysis). Revised: 16 November 2005 and 9 March 2006     

反相高效液相色谱法测定酚类化合物的保留指数

以3种ODS柱分别测定了10种酚类化合物的保留值,以烷基甲酮类作为标准参照物计算保留指数及校正保留指数。结果表明,采用校正保留指数系统,可获得比常规保留指数系统更好的精密度和准确性。     

Influence of Mobile Phase Gradients on the Retention and Separation of Peptides from a Cytochrome-c Digest by Reversed-Phase Liquid Chromatography

Eight new carbon adsorbents derived from polyimide copolymer of 4,4'-bis (maleimododiphenyl)methane and divinylbenzene (BM-DVB) were prepared using a variety of methods. The influence of carbonization, steam or phosphoric acid activation on chemical structure and texture of the carbons has been studied. Adsorption-desorption properties of the carbons were estimated based on recovery determinations for, phenol, its chlorinated derivatives and naphthalene from aqueous solution. The results showed that the best adsorption-desorption properties have polymer-based carbons obtained by high temperature steam activation.Revised: 13 February 2006 and 3 April 2006     

反相液相色谱中同系物体系实验点与预测方程参数间的匹配研究

以波相色谱中溶质计量置换统一保留模型（SDM-R）的二参数、三参数和四参数方程为基础,研究了在预测同系物保留值时实验点与预测方程参数间的匹配关系。用两个实验点,分别以二、三和四参数方程对反相色谱中同系物保留值进行预测,发现预测值与实验值基本相符,但以二参数方程预测结果为最佳。又与其它保留方程的预测结果进行了比较,证实了上述结论。当实验点数增加到4～5个时,多参数方程预测同系物的准确度增加,且明显高于二参数方程。同时还讨论了方程中各参数与同系物碳数间的线性关系,发现二参数方程中的参数遵循同系物变化规律。     

Preparative Liquid Chromatography and Centrifugal Partition Chromatography for Purification of New Anticancer Precursors

In organic synthesis, the purification of reactional intermediates or final products is generally carried out by normal phase flash chromatography. However, for dihydrodipyridopyrazines, a new family of antitumor agents, the efficiency of this technique is too low to achieve the purification of the isomer mixture. Purification of the DHDPP isomer mixture has therefore been studied using preparative liquid chromatography. With the stationary phase used in flash chromatography, PLC provides greater efficiency and allows to increase the mobile phase flow rate. A complete study of preparative purification was performed, including that of compounds solubility and analytical optimization. This work has allowed to lower the overlap between the two DHDPP isomers, to greatly reduce the total duration of the process, to increase the purified quantity per run and consequently to greatly improve the throughput of the purification. In addition, this technique can be easily and totally automated. Concurrently, another purification method (centrifugal partition chromatography ), based on acidic constants difference of the two components in two immiscible liquids, was developed. CPC has demonstrated its ability to separate the two DHDPP isomers. Finally, the economic aspects of PLC and CPC results are compared.     

反相液相色谱中溶质保留参数间的定量关系研究

 比较了Snyder经验公式中的K0w 与S和溶质计量置换保留模型 (SDM R)中溶质保留参数Z(1mol溶剂化溶质被溶剂化固定相吸附时 ,在其接触表面处释放出溶剂或置换剂的总摩尔数 )与lgI(与 1mol溶质对固定相的亲和势有关的常数 )之间的定量关系。SDM R中的两个参数间不仅对同系物溶质可以有很好的线性关系 ,而且对非同系物溶质也有很好的线性关系。其线性关系的好坏主要取决于这两个参数数值范围的大小 ,与文献中报告的线性关系取决于是否单因素影响溶质的保留和完全由统计学规律决定的结论不同。     

反相高效液相色谱对8种噻唑类衍生物保留性能的研究

在ＯＤＳ反相柱上，考察了不同浓度下的甲醇／水对８种噻唑衍生物保留值的影响。并把不同浓度的冲洗剂所得保留值和关系式ｌｎＫ′＝ａ＋ｃＣｂ中的参数ａ、ｃ作线性关联，得到很好的相关性，同时考察了不同种类的无机盐和有机胺对噻唑类衍生物容量因子ｋ′的影响。     

反相高效液相色谱法对八种吡嗪类化合物保留性能的研究

在Ｓｐｈｅｒｉｓｏｒｂ－Ｃ（１８）反相柱上,以甲醇－水为流动相,对八种吡嗪类化合物的保留性能进行了考察。同时用不同浓度下的冲洗剂所得保留值和关系式ｌｎｋ＇＝ａ＋ｃＣｂ中的参数ａ、ｃ作线性关系,得到很好的相关性。流动相中不同的无机盐及微量有机胺类改性剂的加入,可有效地改进分离。当甲醇：０．２ｍｌ／ＬＨＡｃ－ＮａＡｃ缓冲液（ｐＨ４．５）：三乙胺为４０：５９：１（Ｖ／Ｖ）时,除两种同分异构体不能分离外,所有组分在２５ｍｉｎ内可实现较理想的分离。     

Measurement of Retention Indexes on n-Alkane Scale in Reversed-Phase Liquid Chromatography and their Prediction from Molecular Structures

Abstract

A method was proposed in which the retention indexes (RI) defined on the n-alkane scale were measured by using 1-phenylalkane homologous series as reference compounds. Good agreement was observed between the RI values obtained with this method and those determined using n-alkanes as the reference. An attempt was made to predict the RIs based on the additivity for the constitutive atomic groups. The RIs were estimated with considerable accuracy by using increments of substituents themselves and positional increments between substituents. It was possible to distinguish methylnitroaniline isomers by comparison of the calculated RI values with the observed values.     

Method Development for the Determination of Seven Organic Acids in Wines by Reversed-Phase High Performance Liquid Chromatography

A simple high performance liquid chromatographic method is described for the determination of seven organic acids usually found in wines. The acids were eluted in the isocratic mode, in less than 12 min, on a reversed-phase ODS-2 (250 × 4 mm I.D.), 5 m, column with 0.02 M potassium dihydrogen phosphate (pH 2.88), to which was added a small amount of methanol (2%) as organic modifier, and were detected by ultraviolet absorbance at 230 nm. Galacturonic, tartaric, malic (both enantiomers), lactic, acetic, citric and succinic acids were determined, using xanthine as a chromatographic internal standard. The method was applied to white and red wines of Greek origin, after sample clean-up with polyvinylpyrrolidone, followed by passage through SAX cartridges and yielded recoveries from 78.0 to 106.8%. The limits of detection ranged between 0.001–0.05 g.L^–1 and the linear ranges between 0.003–2.0 g.L^–1.     

反相高效液相色谱法测定碘

建立了碘的反相高效液相色谱测定方法。色谱条件为：Ｓｈｉｍ－ｐａｃｋ ＣＬＣ－ＯＤＳ柱；流动相为甲醇－水（２０：８０）；流速为１ｍＬ／ｍｉｎ；检测波长为２９０ｎｍ。本方法的线性范围为０．１０￣１０ｍｇ／Ｌ；相对标准偏差为１．１％￣１．４％；加标回收率为９７％￣１０１％。所建立的方法已用于医用碘酒的测定。     

四苯基卟啉金属螯合物的反相高效液相色谱保留行为研究

 研究了四苯基卟啉金属螯合物(TPP)的高效液相色谱保留行为。在C18柱上试验以各种有机溶剂洗脱金属螯合物,最终选择了甲醇-丙酮的非 水体系作流动相。各螯合物的保留顺序为：ZnTPP＜TPP＜NiTPP＜CuTPP。运用Horvath的疏溶剂理论解释了这种保留行为。文中采用电负性与离子半径之比（EN／ri）作为静电场强的量度,提出 EN／ri值作为四苯基卟啉金属螯合物保留值参数。实验发现,在不同的流动相配比条件下,lnk′与 EN／ri均呈良好的线性关系。     

蛋白质在疏水色谱中保留的热力学参数的测定

研究了0～50℃内五种蛋白质在疏水色谱(HIC)中的保留行为。蛋白分子在HIC中的保留行为遵循Van'tHoff方程,并求得蛋白质分子在HIC中保留的热力学参数(△H°,△S°,△C°p和△G°)。发现蛋白质的保留由熵控制,焓、熵和热容量三个热力学参数都与绝对温度倒数间存在线性关系,并求得热容量为零的收敛温度。     

液相色谱手性拆分机理的热力学方法研究

手性识别是分子识别的一个重要组成部分。液相色谱手性拆分机理研究有助于色谱条件的优化和新型手性固定相的设计,也有助于理解手性识别机制。本文就线性色谱与非线性色谱条件下手性拆分过程对应热力学参数的推求方法进行了评述,阐述了相关热力学参数的涵义及其在色谱保留及手性拆分机理探讨中的应用,并展望了该领域的研究前景。     

液相色谱手性拆分机理的热力学方法研究

手性识别是分子识别的一个重要组成部分。液相色谱手性拆分机理研究有助于色谱条件的优化和新型手性固定相的设计,也有助于理解手性识别机制。本文就线性色谱与非线性色谱条件下手性拆分过程对应热力学参数的推求方法进行了评述,阐述了相关热力学参数的涵义及其在色谱保留及手性拆分机理探讨中的应用,并展望了该领域的研究前景。     

氨基苯磺酸和氨基萘磺酸在反相离子对色谱和离子色谱中分离行为的比较

本文考察了氨基苯磺酸和氨基萘磺酸染料中间体在反相离子对色谱和离子色谱中的分离行为，结果表明一些异构体在反相色谱中的保留顺序与离子色谱中的顺序发生颠倒。静电作用力在离子色谱中对保留值的贡献比在反相离子对色谱中对保留值的贡献要大，而疏水作用力在反相离子对色谱中对保留值的贡献却较在离子色谱中对保留值的贡献要大。离子对色谱更有利于有机离子的分离分析。     

Chiral Resolution of the Enantiomers of New Aromatase Inhibitors by Liquid Chromatography on Amylose Stationary Phases

Analytical HPLC methods for derivatized amylose chiral stationary phases were developed for the direct enantioseparation of substituted [1-(imidazo-1-yl)-1-phenylmethyl)] benzothiazolinone and benzoxazolinone derivatives with one stereogenic center. These analogues of fadrozole constitute new potent nonsteroidal inhibitors of aromatase (P450 arom.). The separations were made using normal phase methodology with mobile phase consisting of n-hexane-alcohol (ethanol, 1-propanol or 2-propanol) in various proportions, and a silica-based amylose tris-3,5-dimethylphenylcarbamate (Chiralpak AD), or tris-(S)-1-phenylethylcarbamate (Chiralpak AS). The effects of concentration of various aliphatic alcohols in the mobile phase were studied. Baseline separation (R_s > 1.5) was easily obtained in all cases, ethanol being often the more interesting modifier. The effects of structural features of the solutes along with the temperature of the column on the discrimination between the enantiomers were examined for different mobile phase compositions.