Improvement of the inverse-gated-decoupling sequence for a faster quantitative analysis by 13C NMR

Abstract The inverse-gated-decoupling sequence enables quantitative 1H decoupled 13C spectra to be obtained. We modified this sequence so as to obtain the same result in less time. For that, we determined the optimal 13C longitudinal-magnetisation initial value for a faster relaxation while 1H decoupler is stopped. This value can be calculated via the longitudinal relaxation times and the nuclear Overhauser effects. For a given nucleus, a supplementary delay of 1H decoupling and/or a pulse at the beginning of the recovery delay allows an acceleration of the 13C longitudinal relaxation. We checked this result on the molecule of N,N-dimethylacetamide. A simultaneous quantitative analysis of all carbons was carried out with a recovery delay divided by four compared to the usual sequence. To cite this article: P. Giraudeau et al., C. R. Chimie 9 (2006).