GB/T 37363.3-2020 "Determination of biocide content in coatings - Part 3: Determination of triclosan content" is applicable to the determination of triclosan content in coatings, coating films, and raw materials used in coatings. It specifies the liquid chromatography method and the liquid chromatography-tandem mass spectrometry method. Using methanol as the extraction solvent, the samples undergo ultrasonic extraction, centrifugation, purification, and filtration before being detected by the respective instruments. The external standard method is used for quantification, with a 0.45μm filter membrane for the liquid chromatography method and a 0.22μm filter membrane for the tandem mass spectrometry method. The standard also specifies requirements for the preparation of standard solutions, sample pretreatment, and chromatographic conditions.