提出用顶空采样法富集水样中12种氯代苯胺类化合物，经气相色谱分离后用质谱法测定其含量。试验选择了最佳顶空条件。取水样8.00 mL置于顶空瓶中，加入碳酸钠3.4 g（盐析剂）和0.500 mg·L^-1内标溶液8 μL，于80℃恒温条件下振荡40 min。测定的12种化合物以气体状态进入DB-35MS色谱柱，按程序升温模式进行分离；质谱测定中，采用电子轰击离子源和选择离子监测模式。12种氯代苯胺类化合物的质量浓度在一定范围内与其峰面积呈线性关系，其检出限（3.14s）在0.03~0.3 μg·L^-1之间。按标准加入法进行回收试验，测得回收率在86.0%~131%之间，测定值的相对标准偏差（n=6）在3.0%~20%之间。

Headspace (HS) sampling was applied to enrich 12 chloroanilines in water samples, and the analytes were then separated by GC and determined by MS. Optimum conditions for HS treatment were studied in detail. 8.00 mL of the water sample were placed in the HS-flask, and 3.4 g of Na₂CO₃ (as salting-out reagent) together with 8 μL of 0.500 mg·L^-1 internal standard solution were added. The mixture was shaken for 40 min at constant temperature of 80℃. 12 chloroanilines to be determined were introduced into DB-35MS chromatographic column from the HS-flask and separated under the mode of programmed temperature elevation. In MS analysis, EI and SIM mode were adopted. Linear relationships between values of peak area and mass concentration of the 12 chloroanilines were found in definite ranges, and the detection limits (3.14s) were found in the range of 0.03-0.3 μg·L^-1. Recovery was tested by standard addition method, giving results of recovery in the range of 86.0%-131%. Values of RSDs (n=6) ranged from 3.0% to 20%.