Fig. 1. Comparison characterization data for lignins used in this work showing preservation of β-O-4′ in selected lignin. General overview of the experimental approach for lignin extraction (a), overlayed elution profile of the lignin fractions (b), and the trend of β-O-4′ content for the different lignin fractions, quantified by 2D HSQC, Ar = aromatic rings (c).