نتایج جستجو برای: nmr analysis

تعداد نتایج: 2869644  

Journal: :Magnetic resonance in chemistry : MRC 2005
Vassiliki Exarchou Manfred Krucker Teris A van Beek Jacques Vervoort Ioannis P Gerothanassis Klaus Albert

An overview of recent advances in nuclear magnetic resonance (NMR) coupled with separation technologies and their application in natural product analysis is given and discussed. The different modes of LC-NMR operation are described, as well as how technical improvements assist in establishing LC-NMR as an important tool in the analysis of plant-derived compounds. On-flow, stopped-flow and loop-...

ژورنال: مواد پرانرژی 2017

Simultaneous analysis of explosives to identify, determine the purity and eliminate environmental pollution requires rapid, simple and cheap methods. Spectrophotometries method (UV-Vis), high-field proton nuclear magnetic resonance (1H-NMR), Raman spectroscopy and near infrared (NIR) are common methods that are applicable in two ways of direct and indirect in simultaneous analysis. In this poin...

2004
Takeshi Saito Ryoko Iwasawa Toshihide Ihara Shinichi Kinugasa Akira Nomura Tsuneaki Maeda

LC−NMR has been extensively used for determination and elucidation of chemical structures [1]. In such applications, NMR often suffers poor sensitivity of signal detection. Therefore, stop− flow LC−NMR method, in which flow of LC is stopped when an analyte enters NMR detector, is widely used in order to obtain spectra with sufficient signal to noise ratio to analyze. NMR has been also known tha...

Journal: :Methods in enzymology 2005
Yuanpeng Janet Huang Hunter N B Moseley Michael C Baran Cheryl Arrowsmith Robert Powers Roberto Tejero Thomas Szyperski Gaetano T Montelione

Recent developments provide automated analysis of NMR assignments and three-dimensional (3D) structures of proteins. These approaches are generally applicable to proteins ranging from about 50 to 150 amino acids. In this chapter, we summarize progress by the Northeast Structural Genomics Consortium in standardizing the NMR data collection process for protein structure determination and in build...

Journal: :Chemical reviews 1999
Michael E. Lacey Raju Subramanian Dean L. Olson Andrew G. Webb Jonathan V. Sweedler

B. Reduction in Saddle-Type Coil Size 5 C. Solenoidal Coils and Magic Angle Spinning 5 D. Microcoils 6 E. Microfabrication 7 F. Direct Comparisons of Probe Sensitivity 8 V. Microliter-Volume Static NMR Spectroscopy 9 A. Natural Product Extracts 9 B. Analysis of Combinatorial Chemistry Products 10 VI. Nanoliter-Volume Static NMR Spectroscopy 10 VII. NMR Detection of Capillary Separations 12 A. F...

In this study, a novel amine ionic liquid “Diethanolamine Lactic” [DEA][Lac] was synthesized. The replacement of halogenated ion fluid was used as a modified methodology for the preparation of diethanolamine based on lactic acid. The ionic liquid was characterized using the Fourier transform infrared (FTIR) spectra and the nuclear magnetic resonance (NMR) spectroscopy. The changes in bands' wav...

Molecular modeling analysis of charge density and heat of fornation by PM3 method as well as C, H NMR and 2D-NMR measurements of histidine (substrate) and some of its derivatives as histidine decarboxylase inhibitors were performed. It was established that the atom, usually nitrogen, which forms internal aldimine with pyridoxal5 -phosphate (PLP), (coenzyme), has negative and almost equal ...

Journal: :iranian chemical communication 2014
hassan valizadeh fatemeh mahmoudi kordi zahra hosseinzadeh mir babak bahadori

the species heracleum rawianum belongs to apiaceae, is one of the native species in iran. the leaves and fruits of heracleum rawianium are used traditionally in iran as flavouring agent and spice for food. in the present work, the extraction of aerial parts of this plant with acetone by maceration is described. our phytochemical analysis of the chloroform extract of the aerial parts of this pla...

Journal: :Analytical chemistry 2012
Antoni Beltran Manuel Suarez Miguel A Rodríguez Maria Vinaixa Sara Samino Lluís Arola Xavier Correig Oscar Yanes

Because of the wide range of chemically and structurally diverse metabolites, efforts to survey the complete metabolome rely on the implementation of multiplatform approaches based on nuclear magnetic resonance (NMR) and mass spectrometry (MS). Sample preparation disparities between NMR and MS, however, may limit the analysis of the same samples by both platforms. Specifically, deuterated solve...

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