吹扫捕集-气相色谱-质谱法测定石化土壤中挥发性有机物

DETERMINATION OF VOLATILE ORGANIC COMPOUNDS IN PETROCHEMICAL SOILS USING PURGE-AND-TRAP-GC-MS METHOD

采用吹扫捕集-气相色谱-质谱法,建立了土壤中59种挥发性有机物(VOCs)的监测手段,考察了吹扫温度、吹扫时间和脱附时间等前处理条件的影响。吹扫捕集-气相色谱-质谱法的检出限为0.1~5.0 ng g,相对标准偏差RSD为0.9%~12.5%,土壤空白加标回收率为68.7%~128.7%。所建立的方法可以满足土壤中VOCs的监测要求。从实际某石化企业污水处理厂土壤(简称石化土壤)样品的分析结果可以得出:大部分样品属于低浓度石化土壤样品,可以直接采用吹扫捕集-气相色谱-质谱法进行测定;极少数高浓度石化土壤样品需要用甲醇提取-提取液进样的方法对样品进行前处理;但对于含有未被识别的烷烃和C9以上芳烃污染物的土壤,除标准方法外,需要开发新的分析手段。

A method was established for determination of 59 volatile organic compounds(VOCs)in soils by gas chromatography-mass spectrometry with purge-and-trap pretreatment.The effects of pretreatment conditions such as purging temperature,purging time and desorption time were investigated.The detection limits were 0.1-5.0 ng g,and the recoveries of spiked sample were in the range of 68.7%-128.7%with RSD of 0.9%-12.5%(n=6),indicating that the method is suitable for the analysis of VOCs in soils.From the analysis results of actual petrochemical soil samples,it can be concluded that most of the samples belong to low concentration petrochemical soil samples and can be determined directly by purge-and-trap and gas chromatography-mass spectrometry;Very few high-concentration petrochemical soil samples need to be pretreated by methanol extraction-extraction solution injection.However,in addition to standard methods,it is necessary to develop new analytical methods for soils containing unidentified alkanes,and aromatic hydrocarbons above C9.