选择以硅胶为吸附剂的C₁₈膜片为载体，在流量为100 mL·min^-1的条件下使1 L水样流经膜片富集地下水中半挥发有机物（包括有机氯、多环芳烃、多氯联苯及酞酸酯等19种化合物），将膜片移入10 mL棕色小瓶中，加盖密封，在低于6℃条件下保存并运输。在所述条件下30 d内富集于膜片上的有机物有较好的稳定性。膜片上的富集物可用正己烷2.0 mL，在25℃左右超声洗脱10 min。从洗脱液中分取0.50 mL试液，按所设定工作条件用气相色谱-质谱法测定各富集物的含量。应用此方法对不同地域的多组地下水样品进行分析，并取其中3个样品作为基体在3个浓度水平上进行回收试验，测得回收率在75%~112%之间。对7个加标浓度为0.020 μg·L^-1的水样按方法进行富集、洗脱和测定，测定值的相对标准偏差在4.9%~13%之间。此方法延长了在野外采得的样品的稳定保存时间，对在野外科研团队的持续工作带来方便。

C₁₈ membranes with silica gel as adsortent were selected to be carriers for enrichment of semi-volatile organic pollutants from sample of ground-water (1.0 L) at a flow-rate of 100 mL·min^-1. 19 Compounds, including organochlorine pesticides, polycyclic aromatic hydrocarbons, poly-chlorinated biphenyls and phthalates were tested. The C₁₈ membrane with the adsorbates was transferred to and sealed in a 10 mL brown glass bottle, and the adsorbates on the membrane could be kept stable for 30 days at temperatures below 6℃, and transported under this condition. The adsorbates were eluted ultrasonically from the C₁₈ membrane with 2.0 mL of n-hexane at ca. 25℃ for 10 min, and 0.50 mL of the eluate was taken and used for GC-MS analysis. Several groups of ground water samples taken from various areas in our country were analyzed by the proposed method and 3 samples were selected to be used as matrixes in tests for recovery by standard addition at 3 concentration levels, the results of recovery found were in the range of 75% to 112%. Seven samples with addition of 0.020 μg·L^-1 of the substitute standard in each sample were analyzed by the proposed method, giving values of RSDs (n=7) in the range of 4.9% to 13%. By using the conditions given in this method, the time of presevation of the adsorbates on the C₁₈ membrane in their stable states were extended to 30 days, which was not only advantageous for storage and transportation of the analytes, but also facilitative for long-term field scientific works.