The ISO 15320:2011 standard specifies a method for the determination of pentachloro-phenol (PCP) in aqueous extracts of pulp, paper and Cardboard. This method is suitable for all types of pulp, paper and Cardboard, especially products that come into contact with food. The pentachloro-phenol in the sample is obtained by hot and cold water extraction, condensed by solid phase extraction, acetylated derivatization treatment, and quantified by Gas chromatography, CG (CRP or MS Detector). The results are expressed in milligrams per kilogram of material. This standard provides a uniform detection method for assessing pentachlorophenol residues in paper products, which helps to ensure the safety and environmental friendliness of paper products, especially in the field of food Encasement.