采用双柱和双检测器气相色谱法测定了污染土壤中23种有机氯农药(OCP′s)和7组亚老哥尔。取20 g自然风干粒径小于0.30 mm的土壤样品,用二氯甲烷超声萃取3次,提取液于40 ℃吹氮浓缩并转换成正己烷溶液,浓缩至1 mL。仅测定亚老哥尔时用浓硫酸净化法;仅测定OCP′s时用弗罗里硅土小柱或硅胶净化;同时测定OCP′s和亚老哥尔时,用硅胶小柱分步洗脱净化。样品的浓缩液中如存在大分子干扰物,则用GPC净化。经净化的试液浓缩至1 mL供气相色谱分析。OCP′s根据标准溶液在双柱上的保留时间定性,外标法定量;对亚老哥尔,每组选3~5个校准峰,与基准谱图拟合定性,以校准峰的平均值进行定量。OCP′s和亚老哥尔的检出限依次为0.001,0.002 5~0.005 mg·kg-1,平均回收率依次在82.1%~103%,83.5%~94.7%之间。

GC with dual capillary columns and dual ECD was applied to the determination of 23 OCP′s and 7 groups of aroclor in polluted soil. 20 g of soil sample were extracted ultrasonically thrice with CH2Cl2, and extracts were concentrated at 40 ℃ by N2blowing and converted into nhexane solution with its volume concentrated to 1 mL. The concentrate was purified by conc. H2SO4 (for detn. of aroclor only), or by florisil column or silica gel column (for detn. of OCP′s only). For determination of both aroclor and OCP′s, the concentrate was purified by stepwise elution with silica gel column. Macromolecular impurities were removed by GPC. The purified solution, after concentrating to 1 mL, was used for GC analysis. Identification of OCP′s was made by referring to the retention time of the referential standards on the columns and quantification was made by external standard method. Qualification of aroclor was made by fitting with the spectra of primary standards and quantification was made on the base of average values of the calibration peaks (3-5 peaks should be chosen in the test). Detection limits found for OCP′s and aroclor were 0.001 mg·kg-1, 0.002 5-0.005 mg·kg-1 respectively, and values of av. recovery found were in the ranges of 82.1%-103% (for OCP′s) and 83.5%-94.7% (for aroclor).