Nuclear Magnetic Resonance Identification of Substitutional Isomers in Chelated Polycyclic Aromatic Systems1

1963 ◽  
Vol 28 (11) ◽  
pp. 3216-3217 ◽  
Author(s):  
A. L. Porte ◽  
H. S. Gutowsky
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Polycyclic Aromatic ◽  
Substitutional Isomers ◽  
Nuclear Magnetic

Nuclear magnetic resonance spectra of polycyclic aromatic compounds. I. ABCD systems in fused rings

1964 ◽  
Vol 17 (2) ◽  
pp. 163 ◽  
Author(s):  
TJ Batterham ◽  
L Tsai ◽  
H Ziffer
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Theoretical Study ◽  
Polycyclic Aromatic Compounds ◽  
Theoretical Treatment ◽  
Aromatic Rings ◽  
Nuclear Magnetic Resonance Spectra ◽  
Polycyclic Aromatic ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

A theoretical study of the nuclear magnetic resonance spectra given by ABCD systems in fused aromatic rings is presented. The symmetry of these systems allowed much simplification and equations developed for an R-AB-X case made possible the allocation of the lines to specific transitions. Examples are given to show how the theoretical treatment makes possible an analysis of observed spectra.

Use of 13C Nuclear Magnetic Resonance To Assess Fossil Fuel Biodegradation: Fate of [1-13C]Acenaphthene in Creosote Polycyclic Aromatic Compound Mixtures Degraded by Bacteria

1998 ◽  
Vol 64 (4) ◽  
pp. 1447-1453 ◽  
Author(s):  
Sergey A. Selifonov ◽  
Peter J. Chapman ◽  
Simon B. Akkerman ◽  
Jerome E. Gurst ◽  
Jacqueline M. Bortiatynski ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Mixed Culture ◽  
Isotope Labeling ◽  
Partial Transformation ◽  
Polycyclic Aromatic Compound ◽  
13C Nuclear Magnetic Resonance ◽  
Polycyclic Aromatic ◽  
C Nmr ◽  
Nuclear Magnetic

ABSTRACT [1-13C]acenaphthene, a tracer compound with a nuclear magnetic resonance (NMR)-active nucleus at the C-1 position, has been employed in conjunction with a standard broad-band-decoupled13C-NMR spectroscopy technique to study the biodegradation of acenaphthene by various bacterial cultures degrading aromatic hydrocarbons of creosote. Site-specific labeling at the benzylic position of acenaphthene allows 13C-NMR detection of chemical changes due to initial oxidations catalyzed by bacterial enzymes of aromatic hydrocarbon catabolism. Biodegradation of [1-13C]acenaphthene in the presence of naphthalene or creosote polycyclic aromatic compounds (PACs) was examined with an undefined mixed bacterial culture (established by enrichment on creosote PACs) and with isolates of individual naphthalene- and phenanthrene-degrading strains from this culture. From13C-NMR spectra of extractable materials obtained in time course biodegradation experiments under optimized conditions, a number of signals were assigned to accumulated products such as 1-acenaphthenol, 1-acenaphthenone, acenaphthene-1,2-diol and naphthalene 1,8-dicarboxylic acid, formed by benzylic oxidation of acenaphthene and subsequent reactions. Limited degradation of acenaphthene could be attributed to its oxidation by naphthalene 1,2-dioxygenase or related dioxygenases, indicative of certain limitations of the undefined mixed culture with respect to acenaphthene catabolism. Coinoculation of the mixed culture with cells of acenaphthene-grown strain Pseudomonas sp. strain A2279 mitigated the accumulation of partial transformation products and resulted in more complete degradation of acenaphthene. This study demonstrates the value of the stable isotope labeling approach and its ability to reveal incomplete mineralization even when as little as 2 to 3% of the substrate is incompletely oxidized, yielding products of partial transformation. The approach outlined may prove useful in assessing bioremediation performance.

Nuclear magnetic resonance spectra of polycyclic aromatic compounds. II. Substituted benz[a]anthracenes

1965 ◽  
Vol 18 (12) ◽  
pp. 1959 ◽  
Author(s):  
TJ Batterham ◽  
L Tsai ◽  
H Ziffer
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Aromatic Compounds ◽  
Approximate Solutions ◽  
Polycyclic Aromatic Compounds ◽  
Nuclear Magnetic Resonance Spectra ◽  
Polycyclic Aromatic ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

The nuclear magnetic resonance spectra of benz[a]anthracene and a number of its derivatives have been analysed and approximate solutions are given. Comparisons have been made between spectra run at 60 Mc/s and 100 Mc/s.

1H NMR metabolomics of earthworm responses to sub-lethal PAH exposure

2009 ◽  
Vol 6 (5) ◽  
pp. 432 ◽  
Author(s):  
Sarah A. E. Brown ◽  
Andre J. Simpson ◽  
Myrna J. Simpson
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Magnetic Resonance ◽  
Aromatic Hydrocarbons ◽  
Metabolic Responses ◽  
Nmr Metabolomics ◽  
1H Nuclear Magnetic Resonance ◽  
Polycyclic Aromatic ◽  
Pah Exposure ◽  
Nuclear Magnetic

Environmental context. Polycyclic aromatic hydrocarbons (PAHs) are common contaminants, but there has been limited research investigating the responses of earthworm exposure to sub-lethal PAH concentrations. In this study, 1H nuclear magnetic resonance (NMR) metabolomics was used to characterise the metabolic responses of Eisenia fetida earthworm exposure in contact tests to 10, 50 and 100 μg cm–2 naphthalene, phenanthrene and pyrene. The findings of this study highlight the potential of metabolomics as a tool for monitoring earthworm responses to sub-lethal concentrations of problematic environmental contaminants. Abstract. Metabolic responses of earthworm exposure to the polycyclic aromatic hydrocarbons (PAHs) naphthalene, phenanthrene and pyrene in contact tests were measured using 1H nuclear magnetic resonance (NMR). Novel metabolites were not detected but principal component analysis (PCA) showed that earthworms exposed to 10, 50 and 100 μg cm–2 naphthalene, phenanthrene and pyrene differed from unexposed (control) earthworms. Partial least-squares-discriminant analysis (PLS-DA) showed that earthworms had statistically significant responses to PAH exposure, except for 10 μg cm–2 naphthalene and 50 μg cm–2 pyrene. Leucine, valine, alanine, lysine and maltose were identified as potential response indicators of PAH exposure, but whether the concentration of these metabolites increased or decreased was PAH- and concentration-dependent. These initial findings reveal the potential of metabolomics for monitoring earthworm responses to sub-lethal PAH exposure and highlight the role of metabolomics as a future tool in ecotoxicology.

An emerging technology: Nuclear magnetic resonance microscopy

1988 ◽  
Vol 46 ◽  
pp. 1000-1001
Author(s):  
M.J. Hennessy ◽  
E. Kwok
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Relaxation Times ◽  
Basic Research ◽  
Local Environment ◽  
Magnetic Resonance Images ◽  
Nmr Microscopy ◽  
Mri Scans ◽  
Temperature Relaxation ◽  
Nuclear Magnetic

Much progress in nuclear magnetic resonance microscope has been made in the last few years as a result of improved instrumentation and techniques being made available through basic research in magnetic resonance imaging (MRI) technologies for medicine. Nuclear magnetic resonance (NMR) was first observed in the hydrogen nucleus in water by Bloch, Purcell and Pound over 40 years ago. Today, in medicine, virtually all commercial MRI scans are made of water bound in tissue. This is also true for NMR microscopy, which has focussed mainly on biological applications. The reason water is the favored molecule for NMR is because water is,the most abundant molecule in biology. It is also the most NMR sensitive having the largest nuclear magnetic moment and having reasonable room temperature relaxation times (from 10 ms to 3 sec). The contrast seen in magnetic resonance images is due mostly to distribution of water relaxation times in sample which are extremely sensitive to the local environment.

Nuclear magnetic resonance microscopy

1989 ◽  
Vol 47 ◽  
pp. 828-829
Author(s):  
Paul C. Lauterbur
Keyword(s):  
Magnetic Field ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magnetic Fields ◽  
Signal To Noise ◽  
Field Gradients ◽  
Useful Signal ◽  
Magnetic Field Gradients ◽  
Observation Times ◽  
Nuclear Magnetic

Nuclear magnetic resonance imaging can reach microscopic resolution, as was noted many years ago, but the first serious attempt to explore the limits of the possibilities was made by Hedges. Resolution is ultimately limited under most circumstances by the signal-to-noise ratio, which is greater for small radio receiver coils, high magnetic fields and long observation times. The strongest signals in biological applications are obtained from water protons; for the usual magnetic fields used in NMR experiments (2-14 tesla), receiver coils of one to several millimeters in diameter, and observation times of a number of minutes, the volume resolution will be limited to a few hundred or thousand cubic micrometers. The proportions of voxels may be freely chosen within wide limits by varying the details of the imaging procedure. For isotropic resolution, therefore, objects of the order of (10μm) may be distinguished.Because the spatial coordinates are encoded by magnetic field gradients, the NMR resonance frequency differences, which determine the potential spatial resolution, may be made very large. As noted above, however, the corresponding volumes may become too small to give useful signal-to-noise ratios. In the presence of magnetic field gradients there will also be a loss of signal strength and resolution because molecular diffusion causes the coherence of the NMR signal to decay more rapidly than it otherwise would. This phenomenon is especially important in microscopic imaging.

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