GB/T 24165-2009 regulates the determination of PCBs in dyestuff products. The standard specifies the requirements of required instruments, such as gas chromatograph - Mass Spectrometer, and specifies the requirements of experimental reagents. For dyestuff samples, the process from collection, pretreatment to extraction of PCBs is specified in detail, and the target substance is separated by appropriate extraction and purification methods. Then the content of PCBs is accurately determined through instrument analysis. This standard provides a powerful tool for the dyestuff industry to monitor product safety, help enterprises control mass, prevent harmful PCBs from exceeding standards, and promote the green and healthy development of the dyestuff industry.