高效液相色谱－核磁共振联用技术及其应用

高效液相色谱－核磁共振（ＨＰＬＣ－ＮＭＲ）在线联用技术是同时进行未知混合物的分离和结构鉴定的最好手段之一。详细介绍了在ＨＰＬＣ－ＮＭＲ联用技术中１Ｈ谱的分辨率、检测限和多重溶剂峰抑制的最新进展，并简要评述了其它分离方法与ＮＭＲ联用情况     

高效液相色谱－核磁共振联用技术及其应用

高效液相色谱－核共共振在线联用技术是同时进行未知混合物的分离和结构鉴定的量好手段之一。详细介绍了在ＨＰＬＣ－ＮＭＲ联用技术中Ｈ谱的分辨率，检测限手多重溶剂峰抑制的最新进展，并简要评述了其它分离方法与ＮＭＲ联用情况。     

STUDIES ON SEPARATION AND DETERMINATION OF THE COUMARINS IN MURRAYA PANICULATA（L）JACK BY RP－HPLC

ＳＴＵＤＩＥＳ　ＯＮ　ＳＥＰＡＲＡＴＩＯＮ　ＡＮＤ　ＤＥＴＥＲＭＩＮＡＴＩＯＮ　ＯＦ　ＴＨＥ　ＣＯＵＭＡＲＩＮＳ　ＩＮ　ＭＵＲＲＡＹＡ　ＰＡＮＩＣＵＬＡＴＡ（Ｌ）ＪＡＣＫ　ＢＹ　ＲＰ－ＨＰＬＣＳＴＵＤＩＥＳＯＮＳＥＰＡＲＡＴＩＯＮＡＮＤＤＥＴＥＲＭＩ...     

固体高分辨核磁共振方法在表面化学研究中的应用

本文从以下三方面介绍固体高分辨核磁共振技术（ＣＰ／ＭＡＳ ＮＭＲ）在表面化学研究中的应用：表面固载化物种的ＮＭＲ研究；表面活性位的ＮＭＲ研究；以及多相催化转化的ＮＭＲ研究。结果表明ＣＰ／ＭＡＳ ＮＭＲ技术是解决表面问题的最方便、最有力的手段之一。     

ANTI-CANCER DRUGS COMPOSED OF NONNOBLEMETAL COORDINATION COMPOUNDS

ＡＮＴＩ－ＣＡＮＣＥＲ　ＤＲＵＧＳ　ＣＯＭＰＯＳＥＤ　ＯＦ　ＮＯＮＮＯＢＬＥＭＥＴＡＬ　ＣＯＯＲＤＩＮＡＴＩＯＮ　ＣＯＭＰＯＵＮＤＳＡＮＴＩ－ＣＡＮＣＥＲＤＲＵＧＳＣＯＭＰＯＳＥＤＯＦＮＯＮＮＯＢＬＥＭＥＴＡＬＣＯＯＲＤＩＮＡＴＩＯＮＣＯＭＰＯＵＮＤ...     

烷基多苷的分析测定

ＧＣ、＾１Ｈ－ＮＭＲ和＾１３Ｃ－ＮＭＲ核磁共振技术都能准确地测量出烷基多苷的平均聚合度,可判断出烷基多苷中主要苷类的出峰位置。     

UNUSUAL FORMATION OF ORGANO－NEODYMIUM AND －SAMARIUM CATIOHS AND X－RAY STRUCTURE OF［（MeOCH_2CH_2C_5H_4）_2Sm（thf）］［Co（CO）_4］

ＵＮＵＳＵＡＬ　ＦＯＲＭＡＴＩＯＮ　ＯＦ　ＯＲＧＡＮＯ－ＮＥＯＤＹＭＩＵＭ　ＡＮＤ　－ＳＡＭＡＲＩＵＭ　ＣＡＴＩＯＨＳ　ＡＮＤ　Ｘ－ＲＡＹ　ＳＴＲＵＣＴＵＲＥ　ＯＦ［（ＭｅＯＣＨ_２ＣＨ_２Ｃ_５Ｈ_４）_２Ｓｍ（ｔｈｆ）］［Ｃｏ（ＣＯ）_４］ＵＮＵＳＵＡ...     

A STREAM-LINED PROCEDURE FOR DETERMINATION OF STARCH,NON-STARCH POLYSACCHARIDES AND FREE SUGARS IN CEREALS

Ａ　ＳＴＲＥＡＭ－ＬＩＮＥＤ　ＰＲＯＣＥＤＵＲＥ　ＦＯＲ　ＤＥＴＥＲＭＩＮＡＴＩＯＮ　ＯＦ　ＳＴＡＲＣＨ，ＮＯＮ－ＳＴＡＲＣＨ　ＰＯＬＹＳＡＣＣＨＡＲＩＤＥＳ　ＡＮＤ　ＦＲＥＥ　ＳＵＧＡＲＳ　ＩＮ　ＣＥＲＥＡＬＳＡＳＴＲＥＡＭ－ＬＩＮＥＤＰＲＯＣＥＤ...     

STEREOCHEMISTRY OF CYCLIC ORGANOPHOSPHORUS COMPOUNDS－ⅡMETHANOLYSIS OF 2－CHLORO－4－PHENYL－5，5－DIMETHYL－1，3，2－DIOXAPHOSPHORINAN－2－THIONE：RETENTION OF CONFIGURATION AS WELL AS WELL AS RING OPENING ISOMERIZATION

ＳＴＥＲＥＯＣＨＥＭＩＳＴＲＹ　ＯＦ　ＣＹＣＬＩＣ　ＯＲＧＡＮＯＰＨＯＳＰＨＯＲＵＳ　ＣＯＭＰＯＵＮＤＳ－ⅡＭＥＴＨＡＮＯＬＹＳＩＳ　ＯＦ　２－ＣＨＬＯＲＯ－４－ＰＨＥＮＹＬ－５，５－ＤＩＭＥＴＨＹＬ－１，３，２－ＤＩＯＸＡＰＨＯＳＰＨＯＲＩＮＡＮ－...     

N,N—二乙基二硫代氨基甲酸聚氯乙烯酯引发甲基丙烯酸甲…

用铜试剂（Ｎ，Ｎ－二乙基二硫代氨基甲酸钠）取代聚氯乙烯中的部分氯原子制备了Ｎ，Ｎ－二乙基二硫代氨基甲酸聚氯乙烯酯（ＰＶＣ－ＳＲ），研究了紫外光照下ＰＶＣ－ＳＲ引发甲基丙烯酸甲酯（ＭＭＡ）的聚合反应，考察了光照时间、单体浓度、ＰＶＣ－ＳＲ用量及官能度的影响。结果表明，ＰＶＣ－ＳＲ能有效地引发ＭＭＡ聚合，其产物是交联型接枝聚合物，且具有高接枝率和接枝效率。     

Hyphenated HPLC-NMR and its applications in drug discovery

Hyphenated HPLC-NMR is a fast growing technology, allowing rapid and detailed structural characterization of unknown mixtures. The technical aspects of the technology are reviewed on the basis of system configuration, operation, solvent suppression, HPLC and NMR optimization, and detection. The combined use of HPLC-NMR and HPLC-MS is also described and discussed. Various applications of HPLC-NMR and integrated HPLC-NMR-MS in drug discovery, especially in the separation and structure elucidation of drug impurities, reaction mixtures, degradation products, in vitro and in vivo metabolites, and combinatorial library samples, are illustrated.     

HPLC-NMR of fatty alcohol ethoxylates

The application of HPLC-NMR for the analysis of a mixture of fatty alcohol ethoxylates (FAEs) is described. The use of the new generation, cryogenically cooled probes is investigated in respect of the sensitivity advantage that they provide. The FAE mixture is separated using liquid chromatography at the critical point of adsorption. The ability of the method to differentiate between the different end groups and the degree of polymerization of the mixture constituents is investigated. Both on-flow and stop-flow HPLC-NMR techniques were used together with two-dimensional NMR spectroscopy. The results are compared with those obtained by using an evaporative light scattering detector for the HPLC.     

Anwendungsbeispiele der direkten HPLC-NMR-Kopplung mit hoher Aufl?sung

Zusammenfassung Durch HPLC-NMR on-line Kopplung ist eine gleichzeitige Trennung und Identifizierung von Komponenten eines Substanzgemisches möglich. Trennbeispiele von Aromaten und Steroiden zeigen die mögliche Anwendungsbreite der Methode durch Messung im Durchfluß-bzw. stop-flow-Verfahren. Durch Verwendung einer mathematischen Filter-Funktion kann annähernd die Qualität von herkömmlichen Routine-Spektren erzielt werden.

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Examples of application of direct HPLC-NMR-coupling with high resolution

Summary With the direct on-line coupling of HPLC-NMR, simultaneous separation and identification in the liquid phase of components in a mixture is possible. Examples carried out on some aromatic compounds as well as steroids show the wide scope of application of this method with either a continuous flow or a stop flow technique. A mathematical resolution enhancement technique is utilized to improve the on-line NMR spectra substantially.

     

Implementation of real-time two-dimensional nuclear magnetic resonance spectroscopy for on-flow high-performance liquid chromatography

Directly coupled HPLC-NMR has become a powerful tool for separation and structural elucidation of unknown compounds. However, there are only a few reports on application of on-flow two-dimensional (2D) NMR in HPLC-NMR. Here we present an alternative method for recording real-time 2D-NMR spectrum (total correlation spectroscopy, TOCSY) on a commercial HPLC-NMR system. The method is based on well-established Hadamard matrix for 2D-NMR frequency encoding. In addition, a modified/improved solvent suppression approach is incorporated. This makes it possible to carry out the experiment with both polar and gradient eluents, the widely used chromatographic conditions. The method is example using a synthesized mixture of three amino acids (His, Phe and Try) and a human urine sample. The method demonstrated here may be utilized for high-throughput structural or unknown component identification and fast dynamic study in a variety of applications.     

Observation of exchangeable protons by high-performance liquid chromatography-nuclear magnetic resonance spectroscopy and high-performance liquid chromatography-electrospray ionization mass spectrometry: a useful tool for the hyphenated analysis of natural products

The first high-performance liquid chromatography-nuclear magnetic resonance (HPLC-NMR) investigation of exchangeable protons of low-molecular-mass natural products is reported. Model alkaloids or crude plant extracts were dissolved in 2H2O-1H2O-MeCN (deuterium oxide-water-acetonitrile) or 2H2O-MeCN and, after direct injection or chromatographic separation, examined in a 60-microl NMR flow probe. Exchangeable amino protons initially detected by HPLC-electrospray ionization mass spectrometry were subsequently identified and investigated by stop-flow 1H-NMR, two-dimensional (2D) total correlation spectroscopy (TOCSY), and 2D nuclear Overhauser effect spectroscopy (NOESY). These experiments extend the applicability of HPLC-NMR for the investigation and structure elucidation of natural products.     

HPLC-NMR在化学品检测中的应用前景

简要介绍高效液相色谱-核磁共振(HPLC-NMR)联用技术。综述了目前HPLC-NMR联用技术在药物代谢研究,天然产物分析以及食品分析等方面的应用。展望了HPLC-NMR在化学品分类鉴定中的应用前景。     

Real-time separation of natural products by ultrafast 2D NMR coupled to on-line HPLC

Hyphenated HPLC-NMR is an extremely efficient analytical tool, which makes it possible to perform on-flow experiments where 1D NMR spectra are obtained in real time as the analytes are separated and eluted from the chromatographic column. However, it is incompatible with multidimensional NMR methods that form an indispensible tool for the study of complex mixtures. Recently, Frydman and co-workers have proposed an ultrafast 2D NMR approach, where a complete 2D NMR correlation can be recorded in a single scan, thus providing a solution to the irreversibility of hyphenated techniques. This paper presents the first implementation of on-line ultrafast HPLC-NMR. Ultrafast COSY spectra are acquired every 12 s in the course of a chromatographic run performed on a mixture of natural aromatic compounds. The results, obtained on a commercial HPLC-NMR setup, highlight the generality of the ultrafast HPLC-NMR methodology, thus opening the way to a number of applications in the numerous fields in which HPLC-NMR forms a routine analytical tool.     

High performance liquid chromatography coupled to nuclear magnetic resonance spectroscopy and mass spectrometry applied to plant products: Identification of ecdysteroids fromSilene otites

Summary HPLC coupled in parallel to nuclear magnetic resonance (NMR) and mass spectrometry (MS) has been used to obtain¹H NMR and mass spectra of a number of ecdysteroids present in an extract of the plantSilene otites. Reversed phase gradient chromatography was performed using a D₂0-acetonitrile-based solvent system. NMR and mass spectra were obtained for integristerone A, 20-hydroxyecdysone, 2-deoxy-20-hydroxyecdysone and 2-deoxyecdysone to provide structural confirmation using continuous and stopped flow HPLC-NMR. The combined HPLC-NMR-MS system described here provided a more comprehensive analysis of the ecdysteroids present in the extract than HPLC-NMR alone.     

Application of HPLC-NMR coupling using C30 phase in the separation and identification of flavonoids of taxonomic relevance

The on-line separation and identification of two important taxonomic markers for plant species of the Paepalanthus genus, the flavonoids 6-methoxykaempferol-3-O-beta-D-glucopyranoside and 6-methoxykaempferol-3-O-beta-D-6"(p-coumaroyl)glucopyranoside, has been performed with an HPLC-NMR coupling using C30 phase. 1D spectra have been recorded in the stopped-flow mode for the two predominant chromatographic peaks. This is the first application of HPLC-NMR coupling using C30 phase to a taxonomic problem. The technique drastically reduces the required amount of sampling for structure determination.     

On-Line Coupling of Separation Techniques to NMR

The hyphenation of chromatographic separation techniques with NMR spectroscopy is one of the most powerful and time-saving methods for the separation and structural elucidation of unknown compounds and molecular compositions of mixtures. Most of the routinely used NMR flow-cells have detection volumes between 40–180 μL for conventional separations with analytical columns, and the newest designs employ detection volumes in the order of 200 nL for capillary separations. The low flow rates used in capillary chromatography permit the use of deuterated solvents. Unequivocal structural assignment of unknown chromatographic peaks is possible by two-dimensional stopped-flow capillary HPLC-NMR experiments.