METHODS The residues of 4 isomers of benzene hexachloride (BHC), 4 isomers of dichloro-diphenyl trichloroethane (DDT) and pentachloro nitrobenzene (PCNB) were determined by gas chromatography.

• 方法 采用气相色谱法对六六六(BHC) 4种异构体、滴滴涕 (DDT) 4种异构体和五氯硝基苯 (PCNB)进行测定。