# Advancing lignin analytics via elucidation of linkage progressions in lignin populations

## TL;DR

This paper introduces a new method using NMR and MALDI-TOF MSn to better understand the complex structures of lignin molecules in mixtures.

## Contribution

The study combines NMR and MALDI-TOF MSn to reveal detailed structural progression in lignin populations.

## Key findings

- NMR and MALDI-TOF MSn together enable precise identification of lignin inter-unit linkages.
- A structural progression map was created to show chemical features of lignin oligomers.
- The method effectively distinguishes molecular heterogeneity in both milled wood and synthetic lignins.

## Abstract

The elucidation of the structures of individual lignin molecules in heterogeneous lignin isolates poses a challenge, underscoring the need for the development of robust analytical methods. Herein, we report the combined use of NMR and MALDI-TOF MSn as a facile approach for distinguishing and determining the detailed structures of individual oligomeric molecules in heterogeneous lignin mixtures. Supported by NMR, MALDI-TOF analysis of acetylated lignins provides precision by enabling the facile discernment of inter-unit linkages in lignin molecules. Furthermore, the progression of lignin linkages could be tracked through population studies, yielding a structural progression map that elucidates the chemical features of individual oligomers in milled wood lignins and synthetic lignins. By unmasking lignin’s molecular heterogeneity, this study marks an essential milestone in lignin analytics with possibility to advance the frontiers of molecular-level research in both fundamental and applied lignin studies.

Elucidating the structures of individual lignin molecules in heterogeneous mixtures remains a significant analytical challenge. Here, the authors employ NMR and MALDI-TOF MSn to precisely discern inter-unit linkages in the lignin molecules, unveiling a structural progression map which elucidates chemical features of individual oligomers in milled wood lignin and synthetic lignin.