Acid Hydrolysis of Wood and Pulp

A substantial proportion of the methods falling into this category consist of the hydrolysis and solubilization of the carbohydrate component of the lignified material, leaving the lignin as a residue which is determined gravimetrically. 

Springer Series in Wood Science Methods in Lignin Chemistry (Edited by S.Y. Lin and C.W. Dence) 

Interfering extraneous materials are removed prior to the hydrolysis step by extraction with an appropriate solvent or combination of solvents. Hydrolysis of the polysaccharides is catalyzed by a variety of strong mineral acids, applied either individually or in combinations. The range of possibilities has been surveyed by Browning (1967a) and Pearl (1967), who also included detailed descriptions of many of the proposed methods. 

2 Determination of Acid-Insoluble (Klason) Lignin in Wood and Pulp 

Ethanol-benzene mixture is prepared by mixing one volume of approximately 95% ethanol and two volumes of C.P. benzene. 

---