Characterizing the lignin sample composition, or the content of carbohydrates and inorganics, is
important because it is claimed to affect the carbon fibre processing steps. Both acid hydrolysis and
the determination of ash content was performed using industry standard methods (41, 42). The
carbohydrate composition after acid hydrolysis was analysed using ion chromatography (IC) using a
DX500 system equipped with a gradient pump GP50 (Dionex) with a flow of 1 ml/min and an
electrochemical detector ED40 (Dionex). The column was a PA1 (Dionex) together with an RP-1
Dionex post-column pump. The eluents was sodium hydroxide, sodium acetate and water at various
compositions.