| Title | Effect of paramagnetic relaxation reagent concentration on the nuclear overhauser enhancement and on the use of gated proton decoupling in quantitative carbon-13 nuclear magnetic resonance
spectroscopy |
| Download | Downloads |
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| Licence | Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences. |
| Author | Ozubko, R S |
| Source | Canada Centre for Mineral and Energy Technology, Energy Research Program, Energy Research Laboratories, Report 78-52 (J), 1978, 25 pages, https://doi.org/10.4095/302018  Open Access |
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| Year | 1978 |
| Publisher | Energy, Mines and Resources Canada |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Subjects | Science and Technology; geochemistry; nuclear applications; carbon isotopes; spectroscopy; paramagnetic minerals |
| Illustrations | schematic models; plots |
| Released | 1978 05 01; 2021 07 20 |
| Abstract | To determine the effect of the concentration of the paramagnetic relaxation reagent chromium (tris)acetylacetonate [Cr(acac)3] when used in quantitative carbon-13 nuclear magnetic resonance spectroscopy
(13C NMR), the spectrum of pyrene, a compound with extreme values of spin lattice relaxation times (T1) and nuclear Overhauser enhancements (NOE), was studied. The NOE, line broadening and shifting of the five pyrene resonances were determined for up
to 0.3 M Cr(acac)3. The quaternary and protonated carbons displayed different NOE's until all were completely quenched with the Cr(acac)3 greater than 0.25 M. Employing this Cr(acac)3 concentration in quantitative NMR analyses eliminated errors due
to differing NOE's, but led to considerable line broadening and shifting. The use of lower Cr(acac)3 concentrations in these analyses, such as the commonly reported 0.05 - 0.15 M, necessitates the joint use of gated proton decoupling to eliminate the
NOE differences which still exist at these concentrations. |
| GEOSCAN ID | 302018 |
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