ISSN:
0025-116X
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
One of the multipulse sequences in FT 13C NMR, the DEPT pulse sequence, was used to decrease the complexity and to improve the information content of 13C NMR spectra of macromolecules such as milled wood lignins (MWL) extracted from hardwoods (Birch and Aspen MWL). This sequence gives the possibility to edit subspectra selectively for CH, CH2 and CH3 carbons, and benefits from a large intensity enhancement for the carbon atom signals, due to polarization transfer. Thus, it is possible to discriminate precisely between quaternary and tertiary aromatic carbon atoms and to show unambiguously the presence of p-hydroxybenzoate structures in Aspen MWL and their absence in Birch MWL. In addition, the DEPT sequence has made possible the observation of signals which, with classical experiments, are overlapped by others signals, either partially, like the C-γ signal of syringaresinol units or completely like the C-α signal in cinnamaldehyde units. Preliminary results indicate that quantitative data might be obtained from the edited spectra.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/macp.1985.021860716
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