Proton nuclear magnetic resonance method

Whenever a higher degree of specificity is mandatory, other techniques have to be employed. A proton nuclear magnetic resonance (PMR) spectroscopic method has been described by Hanna [107] for the direct assay and identifica-... 

Although soil organic matter has been extensively studied by spectroscopic methods, very few investigators have studied peat as a source of humic substances (5-8). This paper presents carbon-13, proton nuclear magnetic resonance (l c-NMR and H-NMR) spectra,... 

Several methods are available in the literature for the measurement of aliphatic amines in biological samples [28]. Problems with specificity and separation and cumbersome derivatisation and/or extraction procedures have limited the use of these techniques on a larger scale in clinical practice. The lack of a simple analytical method may have led to an underestimation of the incidence of the fish odour syndrome. For diagnosing the syndrome, an analytical technique should be used that is able to simultaneously and quantitatively measure TMA and its N-oxide in the complex matrix of human urine. Two such methods are currently available for this purpose proton nuclear magnetic resonance (NMR) spectroscopy and head-space gas analysis with gas chromatography or direct mass spectrometry (see below). 

Use of an integrated system incorporating CCC separation, PDA detector, and LC-MS proved to be a valuable tool in the rapid identification of known compounds from microbial extracts.6 This collection of analytical data has enabled us to make exploratory use of advanced data analysis methods to enhance the identification process. For example, from the UV absorbance maxima and molecular weight for the active compound(s) present in a fraction, a list of potential structural matches from a natural products database (e.g., Berdy Bioactive Natural Products Database, Dictionary of Natural Products by Chapman and Hall, etc.) can be generated. Subsequently, the identity of metabolite(s) was ascertained by acquiring a proton nuclear magnetic resonance ( H-NMR) spectrum. 

The simulated distillation data (Table V and Figures 2, 4, 6) and the FIA analyses of the distillates (Table II) were obtained by standard ASTM methods D2887 and D1319, respectively. The mass spectrometric analyses (MS) of the saturates fractions (Table VI) were obtained by an in-house method similar to that of Hood and O Neal (44). The aromatic fractions were analyzed by the proton nuclear magnetic resonance (NMR) method of Clutter et al. (45), and the results are reported in Tables VII and VIII. 

GAs of previously unknown structure have been fully characterized and their structure determined by a combination of chemical and spectroscopic methods. Proton Nuclear Magnetic Resonance (NMR) spectroscopy provides a great deal of structural information (1+). 13c NMR promises to be a very powerful technique for both structure determination and metabolism studies of GAs ( UO,Ul). Yamaguchi et al. ( Ug) used a combination of proton and 13c NMR to determine the structure of GA o (2 -hydroxy GAg), a minor metabolite of G. fujlkurol. 

Gartland KP, Beddell CR, Lindon JC, Nicholson JK. Application of pattern recognition methods to the analysis and classification of toxicological data derived from proton nuclear magnetic resonance spectroscopy of urine. Mol Pharmacol 1991 39 629 642. 

Basus, V. J. (1989) Proton nuclear magnetic resonance assignments. Methods Enzymol. 177,132-149. 

Albert K, Bayer E. High-performance liquid chromatography proton nuclear magnetic resonance on-line coupling. In Patonay G, ed. HPLC Detection, Newer Methods. New York VCH, 1992 197-227. 

An important contribution to the problem of ir-electron bonding with seven-membered rings is probably made by measurements of the chemical shifts of ring protons as studied by the nuclear magnetic resonance method. It has recently been shown (117) that the displacement of the electron density of the ring protons increases along the series (CsHs)", CeHe, ( 7117)+. Perhaps this expresses the decreasing tendency to enter stable ir-bonds. 

Otvos JD, Jeyarajah EJ, Bennett DW, Krauss RM. Development of a proton nuclear magnetic resonance spectroscopic method for determining plasma lipoprotein concentrations and subspecies distributions from a single, rapid measurement. Clin Chem 1992 38 1632-8. 

Dramatic improvements in instrumentation and methods used for the identification of xenobiotic conjugates (and other metabolites), notably proton nuclear magnetic resonance and mass spectroscopy, have significantly influenced the strategies for the isolation of conjugates. The recently developed soft ionization techniques make it possible to obtain useful mass spectral information for a wide variety of intact underivatized xenobiotic conjugates. The state of... 

Gartland, K.P.R. Beddell, C.R. Lindon, J.C. Nicholson, J.K. Application of Pattern-Recognition Methods to the Analysis and Classification of Toxicological Data Derived from Proton Nuclear-Magnetic-Resonance Spectroscopy of Urine. Mol. Pharmacol. 39(5), 629-642 (1991). 

Fig. 9.—Partial, Proton Nuclear Magnetic Resonance Spectra of 3,4,6-Tri-O-acetyl-l-0-benzoyl-2-chloro-2-deoxy-a-n-glucopyranose in Solution in Degassed Benzene-do. [A. The normal spectrum measured by the Fourier-transform method. B. The spectrum measured with a 3.0-second delay time between the initial, 180°-pulse and the monitoring, 90°-pulse. It should be noted that the resonances of H-5, H-6i, and H-6- have essentially disappeared, leaving the H-2 resonance clearly resolved.]...

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