房丽萍, 封跃鹏, 刘海萍, 吴忠祥

(环境保护部标准样品研究所,北京100029)

同位素稀释气相色谱-质谱法测定土壤/底泥中23种有机氯农药

房丽萍, 封跃鹏, 刘海萍, 吴忠祥＊

(环境保护部标准样品研究所,北京100029)

建立了同位素稀释气相色谱-质谱法(ID-GC-MS))测定土壤/底泥中23种有机氯农药残留的分析方法。样品经干燥、研磨、筛分处理后用250mL丙酮-正己烷(体积比为1∶1)混合溶剂进行索氏提取24h,再经铜粉、凝胶渗透色谱和弗罗里硅土固相萃取柱净化,最后用DB-5毛细管柱进行分离和电子轰击电离源质谱在选择离子监测模式下进行检测,并用13C标记同位素稀释内标法定量。实验结果表明,23种化合物的标准曲线的线性相关性良好,线性范围为50～1 600μg/L,同位素内标的回收率范围为60%～110%,相对标准偏差为1.5%～18%;方法的检出限为0.20～10.3μg/kg。该方法的净化效果较好,定量准确,适用于土壤/底泥这类复杂基质中农药残留的确证分析。

同位素稀释气相色谱-质谱;有机氯农药;土壤;底泥

Abstract:A method was developed for the determination of organochlorine pesticide(OCP)residues in soil/sediment using high resolution gas Chromatography coup led with low resolution mass spectrometry.The analytical p rocedures consisted of Soxhlet extraction,sulfur rem oval with copper powder,clean-up with gel permeation Chromatography(GPC)and a florisil column of solid phase extraction(SPE).The analytes were separated on an HP-5MS capillary column,detected in selected ion monitoring(S IM)mode and quantified using internal standard calibration curves of isotope dilution technique.The linear correlations of calibration standard solutions were good for all the OCPs.The recoveries and relative standard deviations of labeled com pound solutions ranged from60%to110%and from1.5%to18%,respectively.The limits of detection ranged from0.20to10.3μg/kg were established for the23OCPs.The method show ed satisfactory clean-up effect and precision quantification.It is suitable for the determination and confirmation of pesticides in complex matrices such as soil,sediment.

Key words:isotope dilution gas Chromatography-mass spectrometry(ID-GC-MS);organochlorine pesticides(OCPs);soil;sediment

有机氯农药(organochlorinepesticides,OCPs)是《关于持久性有机污染物的斯德哥尔摩公约》中优先控制的12类持久性有机污染物(persistent organic pollutants,PO Ps)之一,具有毒性、亲脂性、半挥发性和生物富集性等特点,可通过食物链进入生物体,易引起生物体内分泌紊乱、生殖及免疫功能失调、发育紊乱等严重疾病[1]。由于其杀虫效果显著而曾被广泛应用,目前虽已禁用多年,但由于其化学性质稳定、持久、难降解,在土壤、底泥中仍能检测到[2-6]。

《关于持久性有机污染物的斯德哥尔摩公约》将9类有机氯农药,即滴滴涕(DD Ts)、氯丹、灭蚁灵、六氯苯、艾氏剂、狄氏剂、异狄氏剂、七氯和毒杀芬列入PO Ps的受控名单。……