GB/T 23990-2009 "Determination of Benzene, Toluene, Ethylbenzene and Xylene Content in Coatings by Gas Chromatography" specifies the method for determining the content of benzene series in coatings, applicable to various types of coating products. After dilution or extraction, the sample is separated and detected by a gas chromatograph equipped with a hydrogen flame ionization detector (FID), with quantification performed using the external standard method. The detection requires instruments such as a gas chromatograph, capillary chromatographic column, and headspace sampler (or solvent extraction device), providing a standardized testing method for the control of benzene series limits in coatings.