逆固相基质分散净化和气质联机法测定土壤DDT残留

Fast Determination of DDT in Soil With GC-MS and Dispersive Solid-Phase Extraction

本文研究了逆固相基质分散净化和气质联机测定土壤中DDT残留量的方法。样品用丙酮/正己烷(1:1,v/v)超声波提取,然后用固相材料吸附净化,用GC-MS(选择离子方式)测定。结果表明,改良后的QuEChERS方法步骤简单,费用低廉,高效准确,方法的添加回收率在99%至107%之间,线性方程的R2>0.99,适合大批量样本快速检测土壤中DDT的残留量。用该法测定了某农药厂周围和厂区地下土壤0.2-10m深的样本115个,为进一步治理提供了数据支持。结果表明,土壤样本中∑DDT(p,p'-DDE,o,p'-DDT,p,p'-DDD,p,p'-DDT)的残留量在0.045mg/kg至14271.96mg/kg之间,多数样本残留量超过国家标准GB15618-1995,DDT在研究地块表现出显著的空间变异趋势,深层土壤样本中p,p'-DDT降解为p,p'-DDD显著。

A simple, fast, and inexpensive method （dispersive solid-phase extraction） was improved to analyze DDT in soils with gas chromatography-mass spectrometry （GC-MS）. DDTs in soil were extracted with acetone/hexane （1.：, v/v） using ultrasonic extraction and removed many polar matrix components using primary secondary amine （PSA） effectively for the purity. GC-MS was then used for quantitative and confirmatory analysis of DDT. Pecoveries between 99 and 107% and P2 〉0.99 have been achieved. Using this method we get the information of DDT quantity in 0.2-10m soils around the DDT factory. The results showed the concentration of ZDDT （ p.p＇-DDE, o.p＇-DDT, p.p＇-DDD, p.p＇-DDT） in the soils changed from 0.045 mg/kg to 14271.959mg/kg. Some concentration of DDT sample exceeded the official Chinese norms for DDT. Significant variations in the contents of the DDT were demonstrated. The p.p＇- DDT was converted to p.p＇-DDD evidently in the deeper soils.