分别从水源、水厂及管网取水样10份，每份水样装满2 L棕色玻璃瓶，各加亚硫酸钠100 mg去除残余氯，于4℃保存，此水样可保存14 d，每升样品中加入20 mg·L^-1苊-d₁₀和屈艹-d₁₂的混合内标溶液100 μL。按国家标准GB/T 5750-2006所述方法进行固相萃取，所得洗脱液经脱水、蒸缩，并用丙酮定容至1.0 mL。选用HP-5MS色谱柱（30 m×0.25 mm，0.25 μm），在55~310℃区间按程序升温模式使此溶液中的23种半挥发性有机物得到分离并进行质谱测定。选择了电子轰击离子源和选择离子监测模式为主要质谱条件。各组分的线性范围除五氯酚为1.00~50 mg·L^-1外，其他均为0.20~10 mg·L^-1，其检出限（3s）在0.03~0.18 μg·L^-1之间。以阴性样品为基体，用标准加入法进行回收试验，测得回收率在75.5%~124%之间，测定值的相对标准偏差（n=6）在1.1%~16%之间。在所取10份样品中均未检出上述各组分，说明水源及水厂（包括经管网输送至用户的水）均符合国家标准中有关半挥发有机物允许最高存在量的相关要求。

Ten portions of water samples taken from the water source, water works and pipeline network, were poured fully and separately into 2 L-brown glass bottles, and 100 mg of Na₂SO₃ were added to each bottle of water sample to expell remained Cl₂. The bottled water samples were kept at 4℃ and should be used for analysis within 14 d. 100 μL of 20 mg·L^-1 mixed internal standard solution of acenaphthene-d₁₀ and chrysene-d₁₂ were added to 1 L each of the water samples, which was then treated by solid phase extraction as described in the national standard of GB/T 5750-2006. The eluate obtained from solid phase extraction was dehydrated, and evaporated to near dryness, and the residue was taken up and made up to 1.0 mL with acetone. The acetone solution was separated by gas chromatography on HP-SMS chromatographic column (30 m×0.25 mm, 0.25 μm). Separation of the 23 semi-volatile organic compounds in the acetone solution was performed under the mode of programed temperature elevation in the temperature interval from 55℃ to 310℃, and determined by MS adopting EI and SIM. Linearity ranges for the semi-volatile organic compounds were found in the same interval between 0.20-10 mg·L^-1, except for pentachlorophenol was in the interval between 1.00-50 mg·L^-1. Their detection limits (3s) were found in the range of 0.03-0.18 μg·L^-1. Recovery was tested by standard addition method using a negative sample as matrix. Values of recovery were found in the range from 75.5% to 124%. Values of RSDs (n=6) were found between 1.1% to 16%. None of the 23 semi-volatile organic compounds was found in the 10 water samples, proving that the quality of city water meets to the requirements of national standards relating to limitations of the semi-volatile organic compounds.