Fig. HSQC Spectrum of Aromatic Region for Vacuum Dried lignin reference sample 2-1
Fig. HSQC Spectrum of Aliphatic Region for Vacuum Dried lignin reference sample 2-1
•
Aromatic Region:
Moderate signal broadening and slight peak shifts are observed, indicating minor structural changes. While the guaiacyl (G) and syringyl (S) units are still detectable, the spectra suggest some level of rearrangement or partial degradation due to the vacuum and thermal conditions.
•
Aliphatic Region:
Side-chain linkages, including β-O-4, are moderately preserved, but there is a noticeable reduction in peak intensity. This suggests mild ether bond cleavage due to the combined effects of vacuum and low temperature.