Nuclear magnetic resonance spectroscopy high-field

Findlay, J. A., and Radies, L. (1980). On the chemistry and high field nuclear magnetic resonance spectroscopy of rapamycin. Can.J. Chem. 58, 579. 

Supercritical fluid chromatography was coupled online to Proton High Field Nuclear Magnetic Resonance Spectroscopy by an specially designed pressure-proof continuous-flow probe head. Separation of phthalate esters was carried out under supercritical conditions using carbon dioxide as eluent. ... 

C., and Chippendale, M., Online coupling of supercritical fluid chromatography and proton high-field nuclear magnetic resonance spectroscopy. Anal. Chem., 66, 3042-3046, 1994. 

Rovnyak D, Hoch JC, Stem AS, Wagner G (2004) Resolution and sensitivity of high field nuclear magnetic resonance spectroscopy. J Biomol NMR 30 1-10... 

The determination of the secondary and tertiary structure—that is, the details of the three-dimensional folding of the polypeptide chain of a protein at high resolution—relies on one of two powerful techniques x-ray diffraction analysis of protein crystals and multidimensional high-field nuclear magnetic resonance (NMR) spectroscopy. Both methods provide very detailed structural in-... 

Due to the complexity of food matrices several advanced spectroscopic techniques have recently been successfully employed to solve authenticity problems, including near infrared spectroscopy (NIR), mid infrared spectroscopy (MIR), low- and high-field nuclear magnetic resonance (NMR), site-specific natural isotopic fiactionation (SNIF-NMR) and... 

The application of high resolution nuclear magnetic resonance spectroscopy to the study of polymer structure is a field which is now about ten years old and has recently grown very rapidly. This technique is employed in nearly every center of polymer research throughout the world and can claim a place as a major tool of macromolecular science. The literature alone can attest to this fact. In preparing recent reviews, I found it necessary to refer to nearly 600 substantial papers, and there are many additional ones of more marginal interest. 

Naughton, D., Whelan, M., Smith, E.C., Williams, R., Blake, D.R. and Grootveld, M. (1993). An investigation of the abnormal metabolic status of synovial fluid from patients with rheumatoid arthritis by high field proton nuclear magnetic resonance spectroscopy. FEBS Lett. 317, 135-138. 

Probably, one of the most valuable advances in this field has dealt with the first chemoenzymatic synthesis of the stable isotope-enriched heparin from a uniformly double labelled 13C, 15N /V-acetylheparosan from E. coli K5. Heteronuclear, multidimensional nuclear magnetic resonance spectroscopy was employed to analyze the chemical composition and solution conformation of N-acety 1 hcparosan, the precursors, and heparin. Isotopic enrichment was found to provide well-resolved 13C spectra with the high sensitivity required for conformational studies of these biomolecules. Stable isotope-labelled heparin was indistinguishable from heparin derived from animal tissues and might be employed as a novel tool for studying the interaction of heparin with different receptors.30... 

M Spraul, M Floffman, P Dvortsak, JK Nicholson, ID Wilson. High-performance liquid chromatography coupled to high-field proton nuclear magnetic resonance spectroscopy application to the urinary metabolites of ibuprofen. Anal Chem 65 327-330, 1993. 

The potential of nuclear magnetic resonance spectroscopy for studying liquid crystalline systems is discussed. Typical spectra of nematic, smectic, and cholesteric mesophases were obtained under high resolution conditions. The observed line shape in the cholesteric phase agrees with that proposed on the basis of the preferred orientation of this phase in the magnetic field. The line shapes observed in lyotropic smectic phases appear to be the result of a distribution of correlation times in the hydrocarbon portions of the surfactant molecules. Thermotropic and lyotropic phase transitions are easily detected by NMR and agree well with those reported by other methods. The NMR parameters of the neat and middle lyotropic phases allow these phases to be distinguished and are consistent ivith their proposed structures. 

Nuclear Magnetic Resonance Spectroscopy. Like IR spectroscopy, NMR spectroscopy requires little sample preparation, and provides extremely detailed information on the composition of many resins. The only limitation is that the sample must be soluble in a deuterated solvent (e.g., deuterated chloroform, tetrahydro-furan, dimethylformamide). Commercial pulse Fourier transform NMR spectrometers with superconducting magnets (field strength 4-14 Tesla) allow routine measurement of high-resolution H- and C-NMR spectra. Two-dimensional NMR techniques and other multipulse techniques (e.g., distortionless enhancement of polarization transfer, DEPT) can also be used [10.16]. These methods are employed to analyze complicated structures. C-NMR spectroscopy is particularly suitable for the qualitative analysis of individual resins in binders, quantiative evaluations are more readily obtained by H-NMR spectroscopy. Comprehensive information on NMR measurements and the assignment of the resonance lines are given in the literature, e.g., for branched polyesters [10.17], alkyd resins [10.18], polyacrylates [10.19], polyurethane elastomers [10.20], fatty acids [10.21], cycloaliphatic diisocyanates [10.22], and epoxy resins [10.23]. 

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