Improved methods for assignment of multiplicity in 13C NMR spectroscopy with application to the analysis of mixtures

Improved methods for the assignment of resonance multiplicity in 13C NMR spectra are described. Assignments are achieved either by direct observation of resonance intensity modulations resulting from gated spin echo (GASPE) experiments, or from the derivation of ‘selected multiplet’ spectra containing only C, CH, CH2 or CH3 carbon resonances. The methods are time‐efficient and, by comparison with the single frequency off‐resonance decoupling assignment technique, show improved spectral resolution. Chemical mixtures are used to illustrate the procedures. Possible application to materials deriving from fossil fuel sources is considered.