张 兵, 吴嘉嘉, 刘国瑞, 高丽荣, 郑明辉

(中国科学院生态环境研究中心,北京100085)

同位素稀释-气相色谱-串联质谱法测定土壤中的指示性毒杀芬

张 兵, 吴嘉嘉, 刘国瑞, 高丽荣, 郑明辉＊

(中国科学院生态环境研究中心,北京100085)

建立了土壤样品中指示性毒杀芬Parlar N o.26(P26)、Parlar No.50(P50)和Parlar N o.62(P62)的同位素稀释-气相色谱-串联质谱(ID-GC-MS/MS)的分析方法。土壤样品使用压力溶剂萃取装置(PLE)提取,以丙酮-正己烷(1∶1,v/v)混合溶液为提取溶剂;提取液依次经由多层酸性硅胶柱和活化硅胶柱净化;洗脱液经氮吹浓缩至20μL后,利用GC-MS/MS的多反应监测(MRM)模式进行定性和定量。结果表明本方法可对样品中的P26、P50和P62进行分析,相对标准偏差(RSD)小于11%,回收率可以达到55%～110%;P26、P50和P62的仪器检出限分别为3.0、3.0和6.0pg。将该方法用于某地区农田表层土壤中3种指示性毒杀芬的检测,其中P26的含量为0.17

ng/g、P50为0.08ng/g、P62为0.09ng/g。此方法适用于土壤样品中指示性毒杀芬的分析。

同位素稀释法;气相色谱;串联质谱;指示性毒杀芬;土壤

Abstract:Although toxaphene is now banned in use,the analysis of toxaphene has attracted increasing interest due to its persistence and widespread atmospheric transport in the environment.A new method based on isotope dilution-gas Chromatography-tandem mass spectrometry(ID-GC-MS/MS)has been developed for the determination of three toxaphene specific congeners comprised of Parlar No.26(P26),Parlar N o.50(P50)and Parlar N o.62(P62)in soil.13C10-labeled indicator toxaphene solution was added to the sample prior to pretreatment.Then the sample was extracted using p ressurized liquid extraction(PLE)follow ed by purification on multilayer acidic silica column and neutral silica column.The eluent was concentrated under gentle nitrogen gas flow and spiked with the injection of internal standard of13C10-chlordane.I-dentification and quantification of the analytes were carried out in the multip le reaction m onitoring(MRM)m ode after the GC separation.The linear range was20-800μg/L for three congeners,limits of detection(LOD)ranged from3.0to6.0pg.The five point calibration curves show ed a good linearity for all the congeners(R2>0.99).The relative standard deviations(RSD s)were below11%for and the spiked recoveries were in the range of55%-110%.The developed analytical method is suitable for the determination of toxaphene specific congeners in soil.

Key words:isotope dilution;gas Chromatography(GC);tandem mass spectrometry(MS/MS);indicator toxaphene;soil

毒杀芬是一种广谱性杀虫剂,由5～10个氯取代的莰烯或莰烷组成,根据其结构式理论推断,它的同类物的数量多达32 768种[1]。在20世纪70年代,毒杀芬被用作滴滴涕(DD T)的替代品,为了保护农作物、家禽和家畜免受害虫和病毒侵害,曾经在世界范围内被广泛使用[2]。由于它具有较高的毒性、持久性和生物富集性,所以可在大气中进行远距离传输[3],在远离使用地点的海洋哺乳动物体内、鱼类甚至是人乳中都检测到了不同浓度的毒杀芬[4-6];毒杀芬已被列为《斯德哥尔摩公约》中首批控制的12种持久性有机污染物(persistent organic pollutants,PO Ps)之一。虽……