2.7 Characterization of recovered lignin structure
Two-dimensional heteronuclear single quantum coherence nuclear magnetic
resonance (2D HSQC NMR) spectra of the fractionated lignin were obtained
on a Bruker AVANCE III HD 800 MHz NMR equipped with a TCI cryoprobe.1H–13C HSQC spectra were processed
from the hsqcetgpsp pulse program with the following acquisition
parameters: 32 scans, 1s of relaxation delay, with F1
(13C) and F2 (1H) dimensions at 160
and 12 ppm spectral, with 512 and 1024 data points, respectively.
Dimethylsulfoxide-d 6(DMSO-d 6) was used as the solvent for lignin.