Solvent Extractives of Wood and Pulp, Test Method T 204 cm-17
This method describes a procedure for determining the amount of solvent-soluble, non-volatile material in wood and pulp. Three different solvent systems may be employed, the selection depending on the safety and reproducibility requirements of each particular laboratory. In general, dichloromethane extraction gives lower amounts of extractives than either acetone or ethanol/benzene. Extraction with 1/3 ethanol and 2/3 benzene typically gives the highest level of extractives due to the additional dissolution of low molecular weight carbohydrates and polyphenols. These generalizations do not apply to all wood species, including some tropical hardwoods containing high molecular weight polyterpene resins.
Because of health, safety and regulatory concerns associated with the use of benzene and dichloromethane, acetone has been added as an alternative solvent for the determination of extractives in wood and pulp.