气相色谱/负化学电离源质谱法测定底泥中的有机氯农药

摘要

建立了气相色谱/负化学电离源质谱(GC-NCI-MS)法测定底泥中24种有机氯农药(OCPs)残留的方法.样品采用索氏提取、硅胶/氧化铝复合柱分离纯化,p,p'DDT、o,p'-DDT采用外标法定量,其余的有机氯农药均采用内标法定量.同时,对气相色谱/负化学电离源质谱(GC-NCI-MS)法与气相色谱/电子轰击离子源质谱(GC-El-MS)法分析有机氯农药残留的比较发现,除DDTs类农药NCI源的响应值低于或等于EI源的响应值之外,其余有机氯农药的NCI源的响应值均高于EI源的响应值.3个平行基质土样本加标验证方法回收率,回收率在80%～101%之间,相对标准偏差(RSD)为4.1%～16.1%;方法检出限(LOD)为0.2～10pg/g.太湖底泥样品巾的六氯苯、HCHs、DDTs和有机氯农药总量测定的结果分别为0.04～6.24、0.07～4.20、0.14～8.53和0.43～11.59 ng/g.%An analytical method based on gas chromatography-negative chemical ionization-mass spectrometry (GC-NCI-MS) was developed for determination of 24 organochlorine pesticides (OCPs) in sediment.It employed Soxhlet extraction and silica gel/alumina column for extraction, purification and seperation.p,p'-DDT and o,p'DDT were quantified by external standard method, other OCPs by internal standard method.Compared with gas chromatography-electron impact ion source-mass spectrometry (GC-EI-MS), all of OCPs except DDTs obtained higher response with GC-NCI-MS.The mean recoveries of the matrix samples spiked with the standard solution were between 80％ ～ 101％ , the relative standard deviation (RSD) ranged from 4.1％ to 16.1％ (n =3), the limit of determination (LOD) was 0.2 ～ 10 pg/g.The levels of hexachlorobenzene, HCHs, DDTs and the total organochlorine pesticides in sediment samples were 0.04 ～6.24, 0.07 ～ 4.20, 0.14 ～ 8.53 and 0.43 ～ 11.59 ng/g,respectively.