Improvement of spectral editing in solids:: A sequence for obtaining 13CH+13CH2-only 13C spectra

An improved spectral editing method for solids is described which allows one to obtain a set of subspectra in roughy two-thirds the amount of time as our original CPPI editing method for the same signal to noise. This improvement is afforded by a new pulse sequence that is used to acquire a (CH)-C-13 + (CH2)-C-13 spectrum which has very little (CH3)-C-13 or nonprotonated carbon contamination, By using this new sequence the (CH)-C-13-only subspectrum is obtained much more efficiently. Criteria for optimizing the signal to noise in the edited subspectra are discussed. (C) 2000 Academic Press.