Partial 13C-1H (HSQC) NMR spectra (aliphatic, aromatic, and anomeric regions) of untreated-, IL-pretreated, and AFEX-pretreated switchgrass before and after cultivation. (A) Analysis of the lignin side chain region (aliphatic region) of the HSQC spectra; 2-O-Ac-β-d-Xylp(R) (X′2) and 3-O-Ac-β-d-Xylp(R) (X′3) are derived by polysaccharides. (B) Partial short-range 13C-1H (HSQC) spectra (aromatic region). Lignin monomer ratios are provided. (C) Polysaccharide anomeric regions of 2D 13C-1H (HSQC) spectra. α-d-Glcp, α-d-glucopyranoside; β-d-Glcp, β-d-glucopyranoside; β-d-Xylp, β-d-xylopyranoside; α-l-Araf, α-l-arabinofuranoside; 2-O-Ac-β-d-Xylp, acetylated β-d-Xylp; 3-O-Ac-β-d-Xylp, acetylated β-d-Xylp; R, reducing end; NR, nonreducing end.