Pure shift NMR spectra are spectra in which the scalar coupling has been removed so that all signals appear as singlets, as in 1D 13C spectra. For 13C spectra the coupling is removed by applying 1H composite pulse decoupling during acquisition. Acquiring a pure shift 1H spectrum, however, is not so easy because applying 1H decoupling during acquisition would saturate the 1H signals and prevent them from being detected. To acquire pure shift 1H NMR spectra two ingenious modifications have been developed to enable removal of the coupling in a 1D 1H spectrum. This technique is known as PSYCHE (Pure Shift Yielded by CHirp Excitation)1.
