NMR Research Today is a free monthly online journal that collates and summarizes the latest research about NMR, including details on nuclear magnetic resonance, structural determination, techniques.

Proton-observed carbon-edited NMR spectroscopy in strongly coupled second-order spin systems.

Henry PG, Marjanska M, Walls JD, Valette J, Gruetter R, Ugurbil K

Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota Medical School, Minneapolis, Minnesota, USA. henry@cmrr.umn.edu

Proton-observed carbon-edited (POCE) NMR spectroscopy is commonly used to measure 13C labeling with higher sensitivity compared to direct 13C NMR spectroscopy, at the expense of spectral resolution. For weakly coupled first-order spin systems, the multiplet signal at a specific proton chemical shift in POCE spectra directly reflects 13C enrichment of the carbon attached to this proton. The present study demonstrates that this is not necessarily the case for strongly coupled second-order spin systems. In such cases NMR signals can be detected in the POCE spectra even at chemical shifts corresponding to protons bound to 12C. This effect is demonstrated theoretically with density matrix calculations and simulations, and experimentally with measured POCE spectra of [3-13C]glutamate.

Published 1 February 2006 in Magn Reson Med, 55(2): 250-7.
Full-text of this article is available online (may require subscription).

© 2005-2008 NMR Research Today. All Rights Reserved.