Determination nuclear magnetic resonance

Sacco, A., Brescia, M. A., Liuzzi, V., Reniero, F., Guillou, C., Ghelli, S., and van der Meer, P. (2000). Characterization of Italian olive oils based on analytical and nuclear magnetic resonance determinations. JAOCS 77, 619-625. 

II. Nuclear Magnetic Resonance Determination of Rates and Mechanisms... 

J. Cason and G.L. Lange, Nuclear magnetic resonance determination of substituent methyls in fatty acids, J. Org. Chem. 29(1964)2107-2108. 

Andrewartha KA, Brownlee RTC, Phillips DR. Fourier-transform nuclear magnetic resonance determination of degree of hydration of dilute solutions of biopolymers. Arch. Biochem. Biophys. 1978 185 423-428. 

Lee ML, Novotny M, Bartle KD (1976) Gas chromatography/mass spectrometric and nuclear magnetic resonance determination of polynuclear aromatic hydrocarbons in airborne particulates. Anal Chem 48 1566-1572. 

K. A. Christensen, D. M. Grant, E. M. Schulman, and C. Walling, Optimal determination of relaxation times of Fourier transform nuclear magnetic resonance. Determination of spin-lattice relaxation times in chemically polarized species, J. Phys. Chem. 78, 1971-1977 (1974). 

Lee, M. L. Novotny, M., Bartel, K. D. Gas Chromatography/Mass Spectrometric and Nuclear Magnetic Resonance Determination of Polynuclear Aromatic Hydrocarbons in Airborne Particulates, Anal. Chem. 45, 1566 (1976)... 

Nuclear magnetic resonance Determines both the size and the qualitative nature of nanoparticles... 

Nuclear magnetic resonance Determination of steric configuration in homopolymers composition of copolymers, including proteins chemical fvmctionality, including oxidation products determination of structural and geometric and substitutional isomerism, conformation, and copolymer microstructure. (a-c)... 

Gelhard G, Bres O, Vargas RM, Vielfame F, Schuchardt UF. H nuclear magnetic resonance determination of the yield of the transesterification of grape seed oil with methanol. J Am Oil Chem Soc 1995 72 1239-1241. 

Nuclear magnetic resonance determinations showed the various (27A-27C)-MA charge-transfer complexes exhibited fairly high equilibrium constants, i eq = 0.18-1.27 liter/mole. Considering this, the equimolar compositions of the copolymers, and all other results, a mechanism for the free-radical-initiated copolymerization of 27A-27D with MA was conceived " [Eq. (4)] ... 

Determining the Parameters of a Petroleum Fraction by Nuclear Magnetic Resonance... 

Freeman R and Hiii H D W 1975 Determination of spin-spin reiaxation time in high-resoiution NMR Dynamic Nuclear Magnetic Resonance Spectroscopy e6 L M Jaokman and F A Cotton (New York Aoademio) p 131-62... 

The barriers to rotation about the N-C bond have been determined b dynamic nuclear magnetic resonance for A -isopropyl (80. 81). propanoic acid (74). A -ethyl (82). N-benzyl. and A -neopentyl substituents (82). Selected values of these barriers are given in Tables VII-6 and VII-7. 

Present day techniques for structure determination in carbohydrate chemistry are sub stantially the same as those for any other type of compound The full range of modern instrumental methods including mass spectrometry and infrared and nuclear magnetic resonance spectroscopy is brought to bear on the problem If the unknown substance is crystalline X ray diffraction can provide precise structural information that m the best cases IS equivalent to taking a three dimensional photograph of the molecule... 

Nuclear magnetic resonance (NMR) spectroscopy (Section 13 3) A method for structure determination based on the effect of molecular environment on the energy required to promote a given nucleus from a lower energy spin state to a higher energy state... 

Proton chemical shift data from nuclear magnetic resonance has historically not been very informative because the methylene groups in the hydrocarbon chain are not easily differentiated. However, this can be turned to advantage if a polar group is present on the side chain causing the shift of adjacent hydrogens downfteld. High resolution C-nmr has been able to determine position and stereochemistry of double bonds in the fatty acid chain (62). Broad band nmr has also been shown useful for determination of soHd fat content. 

Nuclear magnetic resonance (nmr) is a nondestmctive means of measuring the amount of hydrogen in various materials for example, nmr has been used to determine the hydrogen content of coals (251). 

Ideally, a mass spectmm contains a molecular ion, corresponding to the molecular mass of the analyte, as well as stmcturaHy significant fragment ions which allow either the direct deterrnination of stmcture or a comparison to Hbraries of spectra of known compounds. Mass spectrometry (ms) is unique in its abiUty to determine direcdy the molecular mass of a sample. Other techniques such as nuclear magnetic resonance (nmr) and infrared spectroscopy give stmctural information from which the molecular mass may be inferred (see Infrared technology and raman spectroscopy Magnetic spin resonance). 

Analytical methods iaclude thin-layer chromatography (69), gas chromatography (70), and specific methods for determining amine oxides ia detergeats (71) and foods (72). Nuclear magnetic resonance (73—75) and mass spectrometry (76) have also been used. A frequentiy used procedure for iadustrial amine oxides (77) iavolves titratioa with hydrochloric acid before and after conversion of the amine to the quaternary ammonium salt by reaction with methyl iodide. A simple, rapid quaHty control procedure has been developed for the deterrniaation of amine oxide and unreacted tertiary amine (78). 

The melting points, optical rotations, and uv spectral data for selected prostanoids are provided in Table 1. Additional physical properties for the primary PGs have been summarized in the Hterature and the physical methods have been reviewed (47). The molecular conformations of PGE2 and PGA have been determined in the soHd state by x-ray diffraction, and special H and nuclear magnetic resonance (nmr) spectral studies of several PGs have been reported (11,48—53). Mass spectral data have also been compiled (54) (see Mass spectrometry Spectroscopy). 

Among the modem procedures utilized to estabUsh the chemical stmcture of a molecule, nuclear magnetic resonance (nmr) is the most widely used technique. Mass spectrometry is distinguished by its abiUty to determine molecular formulas on minute amounts, but provides no information on stereochemistry. The third most important technique is x-ray diffraction crystallography, used to estabUsh the relative and absolute configuration of any molecule that forms suitable crystals. Other physical techniques, although useful, provide less information on stmctural problems. 

Nuclear magnetic resonance (nmr) spectroscopy is useful for determining quaternary stmcture. The N-nmr can distinguish between quaternary ammonium compounds and amines, whether primary, secondary, or tertiary, as well as provide information about the molecular stmcture around the nitrogen atom. The C-nmr can distinguish among oleic, tallow, and hydrogenated tallow sources (194). 

The glass-tiansition tempeiatuiesfoi solution-polymeiized SBR as well as ESBR aie loutinely determined by nuclear magnetic resonance (nmr), differential thermal analysis (dta), or differential scanning calorimetry (dsc). 

Nuclear Magnetic Resonance Spectroscopy. Nmr is a most valuable technique for stmeture determination in thiophene chemistry, especially because spectral interpretation is much easier in the thiophene series compared to benzene derivatives. Chemical shifts in proton nmr are well documented for thiophene (CDCl ), 6 = 7.12, 7.34, 7.34, and 7.12 ppm. Coupling constants occur in well-defined ranges J2-3 = 4.9-5.8 ... 

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