逆流色谱分离中选择性试剂的应用研究进展

逆流色谱中添加选择性试剂可有效提高分离度,常用选择性试剂主要有金属离子、多糖衍生物、阴离子表面活性剂、离子对、手性试剂、p H-区带逆流色谱中酸碱试剂等6类。该文综述了国内外选择性试剂在逆流色谱分离中的应用研究进展,介绍了其基本原理,阐述了不同选择性试剂的适用范围,并展望了选择性试剂发展的新趋势。     

高效液相色谱分光光度测定痕量金属

评述了90年代柱前衍生高效液相色谱分光光度测定痕量金属离子及形态的新进展,系统地论述了柱前衍生试剂的研究,重点评述了试剂的取代基、辅助络合剂及金属配合物的色谱保留机理。     

气相色谱中的衍生试剂及新进展

硅烷化试剂,烷基化试剂,酰基化试剂,缩合反应试剂等是气相色谱中常用的几种主要衍生试剂,本文对这几类常用的衍生试剂及新进展作了较为全面的阐述。     

科学出版社化学类图书精品推荐

分子探针与检测试剂 (“十五”国家重点图书出版规划项目 )张华山等编著　　 2 0 0 2年 8月出版　　定价 :4 5元本书内容丰富 ,取材新颖 ,充分反映了有机试剂基础理论研究的新进展和新成果。本书共分 12章 ,较全面系统地阐述分析化学及生物分析中的有机试剂、分子及离子荧光探针。内容包括 :光度分析中的有机显色剂、荧光试剂、发光试剂、超分子显色剂的作用原理及应用 ;离子荧光探针、分子荧光探针及其生物活性物质的测定和生命科学研究中的应用 ;高效液相色谱和气相色谱中的衍生试剂及应用。本书可供化学化工、生物技术、冶金、地质、农业…     

烷基苯类化合物Kovats指数的高再现性测定方法研究

1引言烷基本类化合物在OV－101柱上的Kovats保留指数（简称Kovats指数）再现性较差，以至不能直接用文献保留数据定性。本文提出了一种新的Kovats指数的测定、计算方法，较好地解决了这一问题。2实验部分2．1仪器与试剂GC－9A气相色谱仪，配CR－ZA（X）色谱数据处理机。C5～C10烷基本类化合物（Fluca试剂），C6～C11正构烷烃（上海分析试剂厂色谱纯试剂），各组份按相近量配成混合标作。2，2色谱杂件色谱柱：50mXO．2mm（i．d）OV－101格融石英毛细管柱（日本岛津公司），理论塔板数174，000；载气：N；，流速50mL／min（表观值）…     

工业制备色谱

考察了色谱柱放大成80毫米以后的载气选择和净化、色谱柱的效能、进样量、载气线速的选择、色谱柱串联和并联、样品收集等。制取了日产量0.5公斤以内的色谱纯试剂苯、甲苯、正庚烷等多品种高纯试剂。     

地质样品中痕量铊的纸色谱法分离-分光光度法测定

研究了甲基异丁基酮、乙醇、氢溴酸3种试剂混合成均相的展开体系中，色谱纸吸附T1及Na2SO3解脱T1的诸条件，使T1与干扰元素分离而预富集，回收率在98％～102％；准确测定了硫化矿和土壤中的T1；考察了2个样品测定5次的相对标准偏差小于4％，试样分析结果与等离子质谱法、泡沫塑料及活性炭吸附分离-镉试剂2B光度法基本一致。     

吖啶作为检测试剂的磷霉素间接光度反相高效液相色谱研究

以吖啶为紫外检测试剂,研究了强极性弱紫外吸收磷霉素的间接光度色谱,探讨了检测试剂性质、浓度、pH值等因素对色谱保留和检测灵敏度的影响,提出一种测定磷霉素的新色谱方法。     

《功能高分子材料》

全书共分17章，结合功能高分子材料的结构开发性能，制备方法及领域，对离子交换树脂，吸附树脂，离子交换纤维和活性碳纤维，高分子膜分离材料，高分子色谱固定相，高分子试剂。     

烷基吡啶盐和芳基季铵盐作检测和改性剂的羟基酸间接光度高效液相色谱研究

研究了苄基三甲基溴化铵动态改性、十四烷基吡啶盐等“永久性”涂渍的两种反相色谱,系统分离和间接光度检测了强极性、弱紫外吸收羟基酸。测定这些检测和改性试剂在YWG-CH反相填料和甲醇-磷酸缓冲液色谱体系的吸附等温线,探讨试剂在固定相的吸附量和其它因素对羟基酸保留、检测灵敏度的影响及分离检测机理。     

快速色谱

基于柱液相色谱和薄层色谱之间的关系,讨论如何为快速色谱选择流动相,并介绍此技术手工操作的步骤.     

Extraction chromatography of common anions in liquid-liquid anion exchange systems. Part. III. Monobasic aliphatic organic acids and their sodium salts as eluants

Summary The chromatographic behaviour of anions on paper strips treated with tri-n-octylamine (TOA) salts or Aliquat 336 and developed with aqueous solutions of acetic, formic, monochloroacetic or trifluoroacetic acids and their sodium salts was investigated. Liquid-liquid extraction of organic acids by 0.1 M solution of TOA in benzene as well as the anion exchange between benzene solutions of TOA salts or Aliquat 336 (in acetate form) in benzene and aqueous solutions of sodium halides was also studied. It was found that extraction increases in the following order of the acids: CH₃COOOH<HCOOH<CH₂CICOOH<CF₃COOH; the relative affinity of organic anions to the quaternary alkyl-ammonium cation also increase in a similar order. The extraction of acid in excess over the amount necessary to neutralize the amine was observed for all four acids. The R_F values of anions investigated depend markedly on the type of organic acids or their salts and their concentration in the mobile phase. Halide ions are more strongly retained on paper treated with Aliquat 336 as compared with TOA salts. The chromatographic systems investigated offer many possibilities to separate various anion mixtures.Parts and II: refs. [1, 2].     

Unified chromatography: Fundamentals,instrumentation and applications†

The concept of unified chromatography has been in existence for 50 years after the work of Giddings proposing that all modes of chromatography (gas chromatography, liquid chromatography, supercritical fluid chromatography and so on) may be treated together under a single unified theory. His idea was partially fulfilled 23 years later by Ishii, Takeuchi and colleagues, who demonstrated for the first time the possibility to analyze a complex sample containing substances with a wide range of boiling points and polarities in the same instrument and column, just by varying the mobile phase pressure and temperature to change from one chromatographic mode to another. This approach has been demonstrated through application to the separation of complex mixtures in several areas including crude oil, edible oils and polymers. Still, unified chromatography has not yet been fully developed. In the present work, we will review the fundamentals, instrumentation and several applications of the technique. Also discussed are the drawbacks that still hinder development, as well as the recent developments and trends in instrumentation and columns that suggest the most feasible ways forward to the full development of unified chromatography.     

A review of advances in two-dimensional thin-layer chromatography

Although there are many simple thin-layer chromatography (TLC) separations, many more are complex and involve more than a few components, that means having to use special high-performance TLC (HPTLC) plates or microspotting or banding devices to increase its resolving power if developing in only one direction. However, adding a second development to perform two-dimensional TLC (2D TLC) allows even better resolution of complex samples. This is because different modes of chromatography are being invoked by the use of one stationary phase with two mobile phases, bilayer plates, graft TLC, or multidimensional TLC. This paper is a review of recent applications that have benefitted from using 2D TLC in its various forms. They were chosen for their variety of sample types as well as the unique choices of plates and/or mobile phases made by the researchers to yield improved separations.     

Exhibition of the first gas chromatographic work of Erika Cremer and Fritz Prior

Summary In November 1995, theDeutsches Museum, the world's largest technical museum, opened a new branch in Bonn, devoted to achievements after 1945. There, the first gas chromatographic system used by Erika Cremer and Fritz Prior, in 1945–47, in Innsbruck, is exhibited. The new display is described and the early activities of Erika Cremer and her students are summarized.     

TLC as a pilot technique for the optimization of gradient HPLC II. Use of data obtained from RP-18 plates for the prediction of gradient programs in reversed-phase liquid chromatography

Summary A method is described and experimentally verified permitting the determination of the optimal gradient programs in HPLC on the basis of isocratic TLC data. The proposed method has many advantages and can also be used in reversed-phase systems. A satisfactory agreement between the theoretical and experimental of V_R/V_O values has been confirmed. Some discrepancies for more strongly retained solutes are, probably due to the respective equilibrium and nonequilibrium state of the column in isocratic and gradient elution.Part I: Ref. [1].     

Affinity monolith chromatography: A review of general principles and recent developments

Affinity monolith chromatography (AMC) is a liquid chromatographic technique that utilizes a monolithic support with a biological ligand or related binding agent to isolate, enrich, or detect a target analyte in a complex matrix. The target-specific interaction exhibited by the binding agents makes AMC attractive for the separation or detection of a wide range of compounds. This article will review the basic principles of AMC and recent developments in this field. The supports used in AMC will be discussed, including organic, inorganic, hybrid, carbohydrate, and cryogel monoliths. Schemes for attaching binding agents to these monoliths will be examined as well, such as covalent immobilization, biospecific adsorption, entrapment, molecular imprinting, and coordination methods. An overview will then be given of binding agents that have recently been used in AMC, along with their applications. These applications will include bioaffinity chromatography, immunoaffinity chromatography, immobilized metal-ion affinity chromatography, and dye-ligand or biomimetic affinity chromatography. The use of AMC in chiral separations and biointeraction studies will also be discussed.     

Investigation of some modes of flat-bed chromatography

A comparison of different chromatographic methods is presented: column liquid chromatography (CLC), thin layer chromatography (TLC), and continuous-elution flat-bed chromatography (CEFBC), which is in fact a combination of the first two methods. In CEFBC a sample is applied to a sorbent layer in a steady flow of eluent, and the components are detected directly on the layer, or immediately upon leaving it, during the separation process. It is shown that evaluation of the separation processes in CEFBC is best accomplished in terms of the parameters applicable in CLC. The reproducibility of the analytical results obtained by CEFBC is better than in the case of TLC by a factor of 6 to 10, and approaches that known for CLC.     

A reversed-phase/hydrophilic interaction mixed-mode C18-Diol stationary phase for multiple applications

A mixed-mode chromatographic packing material, C18 and diol groups modified silica (C18-Diol), was prepared with controllable hydrophobicity and hydrophilicity. It demonstrated excellent aqueous compatibility and stability in aqueous mobile phase; compared to the traditional C18 column, improved peak shape of basic analytes was also obtained. Additionally, it exhibited both reversed-phase liquid chromatographic (RPLC) and hydrophilic interaction chromatographic (HILIC) performance; the analyte separation scope was thus enlarged, demonstrated by simultaneous separation of twenty acids, bases and neutrals. More interestingly, a novel on-line two-dimensional liquid chromatography on the single column (2D-LC-1C) was established by modifying the high performance liquid chromatographic instrument only with the addition of an extra six-port two-position valve. The early co-eluted components of the extract of Lonicera japonica on the 1st-dimension (RPLC) were collected for the online re-injection to the 2nd-dimension (HILIC) by conveniently varying the mobile phase components. Six more peaks were obtained. The established system was simple, easy operation and low cost, which had advantages in analyzing complicated samples.     

Fast and efficient size-based separations of polymers using ultra-high-pressure liquid chromatography

Ultra-high-pressure liquid chromatography (UHPLC) has great potential for the separations of both small molecules and polymers. However, the implementation of UHPLC for the analysis of macromolecules invokes several problems. First, to provide information on the molecular-weight distribution of a polymer, size-exclusion (SEC) columns with specific pore sizes are needed. Development of packing materials with large pore diameters and pore volumes which are mechanically stable at ultra-high-pressures is a technological challenge. Additionally, narrow-bore columns are typically used in UHPLC to minimize the problem of heat dissipation. Such columns pose stringent requirements on the extra-column dispersion, especially for large (slowly diffusing) molecules. Finally, UHPLC conditions generate high shear rates, which may affect polymer chains. The possibilities and limitations of UHPLC for size-based separations of polymers are addressed in the present study. We demonstrate the feasibility of conducting efficient and very fast size-based separations of polymers using conventional and wide-bore (4.6 mm I.D.) UHPLC columns. The wider columns allow minimization of the extra-column contribution to the observed peak widths down to an insignificant level. Reliable SEC separations of polymers with molecular weights up to ca. 50 kDa are achieved within less than 1 min at pressures of about 66 MPa. Due to the small particles used in UHPLC it is possible to separate high-molecular-weight polymers (50 kDa ≤ M(r) ≤ 1-3 MDa, upper limit depends on the flow rate) in the hydrodynamic-chromatography (HDC) mode. Very fast and efficient HDC separations are presented. For very large polymer molecules (typically larger than several MDa, depending on the flow rate) two chromatographic peaks are observed. This is attributed to the onset of molecular deformation at high shear rates and the simultaneous actions of hydrodynamic and slalom chromatography.