This standard specifies a method for the determination of dichloromethane soluble substances in cellulose, which is applicable to dissolved cellulosic pulps prepared from cotton or wood. Dichloromethane soluble substances (extracts) are usually composed of organic materials in wood or cotton, and this test is used to evaluate the removal efficiency of these substances during pulping and bleaching. The presence of extracts may affect subsequent processing of cellulose, so this method is important for pulp users. The standard follows the principles of international standards and does not cover safety issues. Users need to evaluate the relevant regulations by themselves.