Quantitative infrared determination of lignin in cellulose and hemicellulose

A spectroscopic method is suggested for the quantitative determination of lignin in cellulose-containing materials, which is based on taking a differential spectrum of the test material relative to a standard (cotton cellulose). Test samples are prepared in the form of variable thickness films for ease of compensation. Lignin content is determined from the absorption at the maximum of the 1600 cm^–1 band which is assigned to the valence vibrations of C-C bonds in the lignin aromatic ring. The suggested method could be used in industries concerned with the preparation and processing of cellulose and hemicellulose.