Quantitative Characterization of Modified Lignin Using Solid-State 13C NMR Spectroscopy

Solid-state ¹³C nuclear magnetic resonance (NMR) spectroscopy with magic angle spinning (MAS) and direct polarization (DP) techniques is a valuable tool for quantitative and reliable characterization of lignin derivatives, specifically for determining these chemical structures and the degree of substitution upon chemical modification. In this study, the DPMAS ¹³C NMR spectroscopy was used in a quantitative study of the esterifying reaction in lignin derivatives, which allowed the whole lignin structure to be determined. This quantitative evaluation system using DPMAS ¹³C NMR spectroscopy can be widely utilized for lignin characterization without a specific chemical treatment or decomposition of lignin.