This standard provides two methods for determining the loss of plasticizers in plastics, suitable for testing under different temperature conditions. Method A is used for flowability materials at low temperatures, in direct contact with activated carbon; Method B is used for materials at high temperatures, where the specimen is placed in a metal cage to avoid direct contact with activated carbon. Assess the loss of plasticizers by measuring the mass change of the specimen. These methods are used for long-term Stability studies and quality control of plastic performance.