以甲醇为提取剂,提出了吹扫捕集-气相色谱-质谱法测定土壤中28种挥发性有机化合物(VOCs)含量的方法。称取土壤样品5.0 g,加入甲醇10 mL,振荡静置后吸取250 μL提取液至吹扫瓶中,加入一定量的混合内标溶液,用水定容至10 mL,其中内标质量浓度为10 μg·L^-1。结果显示:28种VOCs标准曲线的线性范围均为1~100 μg·L^-1,检出限为7.4~15.2 μg·kg^-1;对空白样品进行加标回收试验,回收率为79.8%~108%,测定值的相对标准偏差(n=6)为1.9%~12%。方法用于两份实际土壤样品分析,三氯甲烷的测定值为22.6 mg·kg^-1和24.0 mg·kg^-1,其余27种VOCs均未检出。

Methanol was used as extraction agent, a method for the determination of 28 volatile organic compounds (VOCs) in soil by gas chromatography-mass spectrometry with sampling by purging and trapping was proposed. 5.0 g of soil sample was added into 10 mL of methanol. After shaking and settling, 250 μL of extracting solution and a certain amount of the mixed internal standard solution were added into the purging bottle, and made its volume up to 10 mL with water. It was shown that the linear ranges of 28 VOCs standard curves were 1-100 μg·L^-1, with detection limits in the range of 7.4-15.2 μg·kg^-1. Recovery test was made on blank sample by standard addition method, giving results in the range of 79.8%-108%, and RSDs (n=6) of the determined values were in the range of 1.9%-12%. This method was applied to analysis of 2 actual soil samples, with the determined values of chloroform of 22.6 mg·kg^-1 and 24.0 mg·kg^-1, and the other 27 VOCs were not detected.