Document Detail

Molecular structure from a single NMR sequence (fast-PANACEA).
MedLine Citation:
PMID:  20659811     Owner:  NLM     Status:  MEDLINE    
The PANACEA experiment combines three standard NMR pulse sequences (INADEQUATE, HSQC and HMBC) into a single entity, and is designed for spectrometers with two or more receivers operating in parallel. For small molecules it offers a direct route to molecular structure. Often the INADEQUATE feature is the rate-determining step, being limited by the low natural abundance of directly coupled (13)C(13)C pairs. This new version, fast-PANACEA, speeds up this measurement by two alternative schemes. In the first, the individual (13)C sites are excited by selective radiofrequency pulses acting on double-quantum coherence, and encoded according to the rows of a Hadamard matrix. The columns of this matrix are used to decode the experimental data into separate F(2) spectra. This reduction in the number of required scans secures a faster result than the conventional stepwise exploration of the evolution dimension where the Nyquist condition and the resolution requirements must both be satisfied. The second scheme makes use of multiple aliasing in the evolution dimension. Significant speed improvements are achieved by either technique, illustrated by measurements made on samples of menthol and cholesterol. A new stabilization scheme (i-lock) is introduced. This is a software program that corrects the final NMR frequencies based on the observed frequency of a strong X-spin signal. It replaces the conventional deuterium lock, permitting measurements on neat liquids such as peanut oil and silicone oil, and offering advantages where deuterated solvents are undesirable.
Eriks Kupce; Ray Freeman
Publication Detail:
Type:  Journal Article     Date:  2010-07-08
Journal Detail:
Title:  Journal of magnetic resonance (San Diego, Calif. : 1997)     Volume:  206     ISSN:  1096-0856     ISO Abbreviation:  J. Magn. Reson.     Publication Date:  2010 Sep 
Date Detail:
Created Date:  2010-08-23     Completed Date:  2010-12-08     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9707935     Medline TA:  J Magn Reson     Country:  United States    
Other Details:
Languages:  eng     Pagination:  147-53     Citation Subset:  IM    
Copyright Information:
(c) 2010 Elsevier Inc. All rights reserved.
Agilent Technologies, 6 Mead Road, Yarnton, Oxford OX5 1QU, UK.
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MeSH Terms
Chloroform / chemistry
Indicators and Reagents
Magnetic Resonance Spectroscopy / instrumentation,  methods*
Menthol / chemistry
Models, Statistical
Normal Distribution
Reg. No./Substance:
0/Indicators and Reagents; 0/Solvents; 1490-04-6/Menthol; 67-66-3/Chloroform

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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