Use of the DEPT pulse sequence to facilitate the 13C NMR structural analysis of lignins

摘要: One of the multipulse sequences in FT 13C NMR, DEPT pulse sequence, was used to decrease complexity and improve information content NMR spectra macromolecules such as milled wood lignins (MWL) extracted from hardwoods (Birch Aspen MWL). This sequence gives possibility edit subspectra selectively for CH, CH2 CH3 carbons, benefits a large intensity enhancement carbon atom signals, due polarization transfer. Thus, it is possible discriminate precisely between quaternary tertiary aromatic atoms show unambiguously presence p-hydroxybenzoate structures MWL their absence Birch MWL. In addition, has made observation signals which, with classical experiments, are overlapped by others either partially, like C-γ signal syringaresinol units or completely C-α cinnamaldehyde units. Preliminary results indicate that quantitative data might be obtained edited spectra.