Non-linear effects of strong coupling in 13C edited 1H NMR spectra obtained without decoupling
Boumezbeur F, Marjanska M, Henry P, Ugurbil K, Lebon V, Valette J
Analysis of in vivo 13C edited 1H NMR spectra is hampered by spectral overlap, and linear combination modeling is being increasingly used to overcome this problem. Up to now, it was implicitly assumed that isotopomer spectra are linear, i.e. the spectrum of any isotopomer (labeled at several carbon positions) can be linearly decomposed to a basis-set consisting of spectra of isotopomers labeled at only one carbon position. In this work this assumption of linearity is investigated. It is demonstrated that, when 13C decoupling is not performed, the linearity assumption is intrinsically incorrect for strongly coupled systems such as glutamate.