Energy-Resolved Mass Spectrometry as a Tool for Identification of Lignin Depolymerization Products.

Lignin is the largest source of bio-based aromatic compounds in nature, and its valorization is essential to the sustainability of lignocellulosic biorefining. Characterizing lignin-derived compounds remains challenging due to the heterogeneity of this biopolymer. Tandem mass spectrometry is a promising tool for lignin structural analytics, as fragmentation patterns of model compounds can be extrapolated to identify characteristic moieties in complex samples. This work extended previous resonance excitation-type collision-induced dissociation (CID) methods that identified lignin oligomers containing β-O-4, β-5, and β-β bonds, to also identify characteristics of 5-5, β-1, and 4-O-5 dimers, enabled by quadrupole time-of-flight (QTOF) CID with energy-resolved mass spectrometry (ERMS). Overall, QTOF-ERMS offers in-depth structural information and could ultimately contribute to tools for high-throughput lignin dimer identification.