Fig. 7From: Effects of pH on steam explosion extraction of acetylated galactoglucomannan from Norway spruceHSQC 2D NMR spectra of lignin content in biomass residues: a sodium citrate pH 4.0 buffered sample, b no buffer control, c sodium citrate pH 6.0 and d potassium phosphate pH 7.0. 5-hydroxymethylfurfural (5-HMF) and guaiacyl are depicted in the lower right of a, signals are colored and numbered according to the structures they relate toBack to article page