This International Standard specifies a test method for the determination of the content of the following preservative agents: - 2-(thiocyanomethylthio)-benzothiazole (TCMTB); - 4-chloro-3-methylphenol (PCMC); -2-phenylphenol (OPP); - 2-octylisothiazol-3(2H)-one (OIT); in leather by liquid chromatography. Preservative agents are necessary to protect leather from microbiological attack. NOTE The preservative agents 4-chloro-3-methylphenol (PCMC) and 2-phenylphenol (OPP) can also be determined according to ISO 17070 and quantified by means of gas chromatography/mass spectroscopy (GC/MS).