ASE提取-磺化与SPE净化-GC-MS法测定土壤中8种有机氯农药残留量

Determination of 8 Organochlorine Pesticide Residues in Soil by ASE Extraction-Sulfonation and SPE Purification-GC-MS Methods

采用加速溶剂萃取技术,结合磺化与固相萃取小柱净化,建立土壤中8种有机氯农药残留量的GC-MS检测方法。通过优化前处理条件,最终选择加速溶剂萃取,萃取液经温度小于等于35℃,真空度大于260 Pa浓缩;加数滴浓硫酸磺化,有机相经硅酸镁小柱净化,DB-5MS色谱柱分离,结合电子轰击电离源(EI)选择离子监测(SIM)模式,采用内标法进行定量检测。试验表明,8种有机氯农药在0.02~1.00 mg/L范围内线性相关系数r均大于0.999,对土壤样品检出限为0.45~0.93μg/kg。对5.0、20.0、100μg/kg 3个浓度水平的土壤基质加标样品精密度试验下,RSD(n=7)分别为0.4%~2.7%、0.4%~3.8%、0.4%~2.0%;使用有证标准样品进行正确度试验,结果均满足要求。该方法快速准确、环保可靠,可满足土壤样品中8种有机氯农药的高通量检测要求;显著降低实样分析时进样口滴滴涕(DDT)降解现象,衬管寿命延长5倍以上,节约成本同时显著提高检测效率。

A GC-MS method for the determination of 8 kinds of organochlorine pesticide residues in soil was established by accelerated solvent extraction technique combined with sulfonation and solid phase extraction column purification.By optimizing the pretreatment conditions,the accelerated solvent extraction was selected finally,the extraction solution was concentrated by temperature≤35℃and vacuum>260 Pa,the organic phase was sulfonated by a few drops of concentrated sulfuric acid,the organic phase was purified by magnesium silicate column,separated by DB-5MS column,selected ion monitoring(SIM)mode combined with electron impact(EI)ofthe ionization source,and the internal standard method was used for quantitative detection.The results showed that the linear correlation coefficients of 8 kinds of organochlorine pesticides were all more than 0.999 in the range of 0.02-1.00 mg/L,and the detection limit for soil samples was 0.45-0.93μg/kg.Under the precision test of the standard samples added to the soil matrix at the three concentration levels of 5.0,20.0,100μg/kg,the RSD(n=7)was 0.4%~2.7%,0.4%~3.8%and 0.4%~2.0%,respectively.The accuracy test was carried out with certified standard samples,and the results all met the requirements.The method is rapid,accurate,environmentally friendly and reliable,which can meet the requirements of high-throughput detection of 8 organochlorine pesticides in soil samples,significantly reduce the DDT degradation at the injection port during real sample analysis,prolong the liner life by more than 5 times,save cost and significantly improve the detection efficiency.