Indirect determination of chemical shift by coupling evolution during adiabatic pulses.
The use of adiabatic 180 degrees X-pulses within INEPT refocusing periods results in chemical shift-dependent evolution of J-couplings. This has been viewed as a disadvantage and several methods of overcoming it have been suggested. This article shows that there is the potential to use this chemical shift dependence to determine heteronuclear chemical shift without a heteronuclear evolution time. In this way, it possible to estimate heteronuclear chemical shift indirectly from a single one-dimensional proton-observe spectrum and determine it with high accuracy from a extensively-folded two-dimensional proton-observe spectrum.
Howe
Peter W A
PW
Analytical Sciences, Syngenta Limited, Jealott's Hill Research Centre, Bracknell, Berkshire, RG42 6EY, UK. peter.howe@syngenta.com