Nuclear magnetic resonance efficiency

The hyphenation of capillary electromigration techniques to spectroscopic techniques which, besides the identification, allow the elucidation of the chemical structure of the separated analytes, such as mass spectrometry (MS) and nuclear magnetic resonance spectroscopy (NMR) has been widely pursued in recent years. Such approaches, combining the separation efficiency of capillary electromigration techniques and the information-rich detection capability of either MS or NMR, are emerging as essential diagnostic tools for the analysis of both low molecular weight and macromolecular compounds. 

Li, C.-Y. et al., Efficient IH nuclear magnetic resonance method for improved quality control analyses of ginkgo constituents, J. Agric. Food Chem., 52, 3721, 2004. 

This is based on spatial nuclear magnetic resonance of water protons within the body. For a contrast agent to be effective, direct coordination of water molecules to the lanthanide is necessary to impart efficient relaxation of the water protons. Therefore, whilst this has been covered comprehensively in a number of recent reviews... 

Nuclear magnetic resonance logging presents a new and efficient means of hydrate detection. Dallimore and Collett (2005, p. 21) summarize theNMR method as follows ... 

Several spectroscopic techniques, namely, Ultraviolet-Visible Spectroscopy (UV-Vis), Infrared (IR), Nuclear Magnetic Resonance (NMR), etc., have been used for understanding the mechanism of solvent-extraction processes and identification of extracted species. Berthon et al. reviewed the use of NMR techniques in solvent-extraction studies for monoamides, malonamides, picolinamides, and TBP (116, 117). NMR spectroscopy was used as a tool to identify the structural parameters that control selectivity and efficiency of extraction of metal ions. 13C NMR relaxation-time data were used to determine the distances between the carbon atoms of the monoamide ligands and the actinides centers. The II, 2H, and 13C NMR spectra analysis of the solvent organic phases indicated malonamide dimer formation at low concentrations. However, at higher ligand concentrations, micelle formation was observed. NMR studies were also used to understand nitric acid extraction mechanisms. Before obtaining conformational information from 13C relaxation times, the stoichiometries of the... 

The coupling of LC (liquid chromatography) with NMR (nuclear magnetic resonance) spectroscopy can be considered now to be a standard analytical technique. Today, even more complex systems, which also include mass spectrometry (MS), are used. The question arises as to how such systems are handled efficiently with an increasing cost and a decreasing availability of skilled personal. LC-NMR and LC-NMR/MS combine the well-established techniques of LC, NMR and MS. For each of those techniques, various automation procedures and software packages are available and used in analytical laboratories. However, due to the necessary interfacing of such techniques, completely new demands occur and additional problems have to overcome. 

The formation of complexes containing hydrogen bonds is detected by the same methods as in the case of polyelectrolyte complexes. Moreover, spectroscopic methods such as Infrared, Raman and Nuclear Magnetic Resonance are used as efficient analytical methods. The composition of [proton-donating polymer unit]/[proton-accepting polymer unit] is generally 2/1 to 2/3 in dilute... 

Dear GJ, Plumb RS, Sweatman BC et al. (2000) Mass directed peak selection, an efficient method of drug metabolite identification using directly coupled liquid chromatography-mass spectrometry-nuclear magnetic resonance spectroscopy. J Chromatogr B Biomed Sci Appl 748 281-293... 

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