Improvement of the acetylbromide method for lignin determination within large scale screening programmes

The acetylbromide method for determining the lignin content in wood was imp roved to increase practical feasibility and repeatability when handling a l arge number of samples. E. globulus wood samples with Klason lignin ranging from 16.5% to 24.5%, and acid soluble lignin 3.8%-5.7% (extractive free wo od) were tested. The lignin absorptivities were measured using a MWL and sa mples with known Klason and total lignin content: values of 18.47 lg(-1) cm (-1), 20.77 lg(-1) cm(-1), 25.57 lg(-1) cm(-1) were obtained. When the lign in content is calculated based on the MWL absorptivity, results are approxi mately 3 abs.% higher than the lignin content determined by the standard ac id method. The results of total lignin determination (Klason plus acid solu ble) can be reproduced with high precision by the acetylbromide method.