高效液相色谱表征高聚物*

最常用的测试高聚物的分子量和分子量分布的体积排除色谱(SEC)是高效液相色谱 (HPLC)的一个重要分支,HPLC的另一个重要分支是相互作用液相色谱, 它是20世纪90年代开始用于高分子分离和表征的研究领域。相互作用液相色谱可以根据高分子的化学结构（如共混物组成、共聚物组成、端基）来分离,它比SEC 有更高的分离效率。本文介绍了高聚物液相色谱的分离模式,并就高聚物体积排除色谱、相互作用液相色谱、临界液相色谱和全二维液相色谱用于分离和表征高聚物的研究进展进行了较系统的综述,并对该技术目前存在的问题和今后可能的发展前景进行了探讨。     

多维液相色谱分离技术及其在蛋白质组研究中的应用

对近年来多维液相色谱技术及其在蛋白质组学研究中的应用进行了系统综述。详细描述了由不同液相色谱模式构建的多维液相色谱系统,并介绍了其在蛋白质组表达谱、翻译后修饰、定量等方面的应用。此外,还对多维液相色谱的发展趋势和前景进行了展望。     

《色谱联用技术》（第二版）

该书主要介绍了色谱-质谱、色谱-傅立叶变换红外光谱、色谱-原子光谱和色谱-色谱联用技术。该书简述了质谱、傅立叶变换红外光谱、原子光谱和核磁共振仪器的结构、工作原理、以及与色谱联用时对接口的一般要求。该书内容丰富，包括：液相色谱-质谱、毛细管电泳-质谱、色谱-傅立叶变换红外光谱、液相色谱-傅立叶变换红外光谱、薄层色谱-傅立叶变换红外光谱、色谱-原子光谱等联用技术，以及液相色谱-液相色谱、气相色谱-气相色谱、气相色谱-液相色谱等不同的分离模式色谱联用技术的应用实例。该书是《色谱技术丛书》之分册，在第一版基础上作了修改和充实，补充了新近发展的仪器、技术与应用实例。     

多维液相柱色谱

多维液相柱色谱分离分析复杂样品越来越受到重视。本文介绍了国内外多维液相柱色谱的近期发展,详细讨论了二维液相色谱的实现,其中包括固定相、流动相的选择、温度变量的作用以及两维间切换的实现,并对多维液相柱色谱的应用现状进行了总结。     

中药物质基础的高效液相色谱分离分析方法研究

高效液相色谱方法已成为中药物质基础研究的重要手段．在中药质量控制、中药标准品制备、活性化合物发现等方面发挥着不可替代的作用．然而我们的实验数据表明,一个中药材可能包含上万个化合物．中药物质基础的复杂性对高效液相色谱方法提出了巨大挑战．本文针对液相色谱方法在中药物质基础分离分析中存在的问题与难点,结合红花、黄连、姜黄三味药材样品,从亲水色谱分离模式、新型色谱固定相、二维液相色谱分离系统和液相色谱质谱联用技术等方面讨论了液相色谱的分离分析方法和发展方向．结果表明,高效液相色谱新技术新方法在中药复杂体系的分离分析中具有很大的发展潜力和应用前景．     

芯片液相色谱技术进展

微型化是现代分析仪器发展的重要趋势。微型化液相色谱仪器在提供与常规尺度液相色谱相同甚至更高分离效率的同时,可以有效减少溶剂和样品的消耗;在液相色谱-质谱联用中,低流速进样可以有效提高质谱离子源的离子化效率,提高质谱检测效率;对于极微量样品的分离,微型化的液相色谱可以有效减少样品稀释;液相色谱的微型化还有利于液相色谱仪器整体的模块化和集成化设计。芯片液相色谱是在微流控芯片上制备色谱柱并集成相应的流体控制系统和检测系统。芯片液相色谱是色谱仪器微型化的一种重要方式,受到学术界和产业界的普遍关注,但是这一方式也充满挑战。液相色谱微流控芯片需要在芯片基底材料、芯片色谱柱的结构设计、微流体控制技术、检测器技术等方面做出创新,使微流控芯片系统适配液相色谱分离技术的需要。目前芯片液相色谱领域面临的主要问题在于芯片基底材料的性质难以满足芯片液相色谱进一步微型化和集成化的需求;因此芯片液相色谱在未来的发展中需要着重关注新型微流控芯片基底材料的开发以及微流控芯片通道结构的统一设计。该文着重介绍了芯片液相色谱技术近年来的研究进展,并简要展示了商品化芯片色谱当前的发展情况。     

中国科学院兰州化物所色谱技术研究开发中心

中国科学院兰州化物所色谱技术研究开发中心是我国唯一从事研制、生产高效气相色谱柱、高效液相色谱柱、液相色谱填料以及相关产品的高科技企业。中心致力于我国色谱柱产业核心技术体系的发展,独创出国际领先的液相沉渍。原位一体化合成制备高效PLOT色谱柱技术:拥有先进的超净-静态制备高效WCOT色谱柱技术:在国内率先完成了球形硅胶色谱填料制备研究开发工作,研制开发出多种液相手性分析填料以及国内急需的专用色谱柱,创造出多项     

中国科学院兰州化物所色谱技术研究开发中心

<正>中国科学院兰州化物所色谱技术研究开发中心是我国唯一从事研制、生产高效气相色谱柱、高效液相色谱柱、液相色谱填料以及相关产品的高科技企业。中心致力于我国色谱柱产业核心技术体系的发展,独创出国际领先的液相沉溃、原位一体化合成制备高效PLOT色谱柱技术;拥有先进的超净-静态制备高效WCOT色谱柱技术;在国内率先完成了球形硅胶色谱填料制备研究开发工作;研制开发出多种液相手性分析填料以及国内急需的专用色谱柱;创造出多项     

特殊结构的新型液相色谱填料的研究进展

<正>在高效液相色谱中,提高分离效率和分析速度是色谱工作者关注的永恒主题[1]。从最初的无定型硅胶发展到多孔硅胶、金属氧化物微球以及聚合物整体柱,针对不同的分析目的,已经研制出大量具有特殊结构的液相色谱填料并被产业化,为液相色谱方法的发展提供了更多的选择。近年来,随着超高效液相色谱、二维液相色谱的发展,人们对可极大提高     

微径高效液相色谱法分离三唑类手性化合物的对映体

 采用微径高效液相色谱技术在手性纤维素色谱柱上分离了一系列 1 1,2 ,4 三唑类手性化合物。比较了微径液相色谱与传统液相色谱的分离结果 ,研究了化合物的苯环上不同取代基及取代基位置对分离的影响 ,并探讨了分离机理。     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.     

Synthesis of N-substituted carbazolones from α-iodo enaminones via Pd(0)-catalyzed intramolecular coupling under microwave irradiation

A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd₂(dba)₃-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring.     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Synthesis of substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles by intramolecular nitrilimine cycloaddition

Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles.