取焦化废水样品（500 mL），用二氯甲烷先后萃取3次，每次用此溶剂200 mL，使水样中的多环芳烃（PAHs）溶入有机相。所得萃取液合并后，经脱水并蒸发至0.5 mL，加入d-12苝内标溶液50 μL，定容至1 mL，按规定条件用全二维气相色谱分离后与飞行时间质谱法联用对样品中16种PAHs进行测定。由于采用了二维色谱柱系统（一维RTX-5MS非极性柱和二维DB-17MS极性色谱柱用毛细管串联）并通过二维调制优化，以及对其共流出峰的去卷积解析，使16种PAHs包括沸点相近、极性相似的成分达到完全分离，选择性较好，背景干扰少，保证了信号最弱的组分（10 pg）的信噪比都大于100。16种PAHs的检出限（3S/N）为0.01~0.092 μg·L^-1，其测定值的相对标准偏差（n=5）为2.5%~5.0%。通过仪器数据处理软件，建立了该类废水中整体有机物的比对方法，用于评估生化处理前后废水中有机物的组成变化。

A portion of coking wastewater (500 mL) was extracted thrice with CH₂Cl₂ (200 mL for each extraction) in succession, to have the polycyclic aromatic hydrocarbons (PAHs) transfered into the organic phase. The extracts were combined, dehydrated and evaporated to 0.5 mL, and d-12 perylene solution (50 μL) was added as internal standard and the volume of the solution was made up to 1 mL, which was then introduced into the instrument for GC separation using comprehensive 2-dimensional GC column system (1-dimensional RTX-5MS weakly polar column and 2-dimensional DB17-MS polar column connected in series by capillary tube) and the 16 PAHs were determind by TOF-MS. Due to the application of 2-dimensional GC separation, with optimuzation by modulation and deconvolution of the co-effused peaks, the 16 PAHs, including those compounds having very close boil pounts and similar polarities, were separated completely, with fine selectivities and less background interferences, and values of S/N ratio>100 were obtained even for those trace components (10 pg) giving very weak signals. Values of detection limits (3S/N) for the 16 PAHs were found in the range of 0.01-0.092 μg·L^-1, and RSDs (n=5) found from their determined values ranged from 2.5% to 5.0%. By using the data-processing software of the instrument, method for comparative study of total organic compounds in wastewater of this kind was established and used for comment on changes of composition of organic compounds in such wastewater before and after bio-chemical treatment.