气相色谱-串联质谱法测定土壤中的有机氯农药

Determination of organochlorine pesticides in soils using gas chromatography-tandem mass spectrometry

建立了气相色谱-串联质谱测定土壤中有机氯农药的方法,同时测定了上海郊区的20个农业土壤。样品前处理包括加速溶剂萃取(弗罗里硅土池内净化)和凝胶渗透色谱净化在线浓缩。采用多反应监测模式的气相色谱-串联质谱分析有机氯农药,降低了背景干扰,提高了分析的灵敏度。在0.001～2mg/L的质量浓度范围内,各种农药标准溶液的线性相关系数均大于0.995。分别向3种实际土壤样品中添加农药的混合标准溶液,所测定的有机氯农药的平均回收率为65.9%～140.0%,相对标准偏差为1.5%～20.3%(n=5)。有机氯农药的检出限(S/N=3)为0.1～3.0μg/kg,定量限(S/N=10)为0.3～8.0μg/kg。实际土壤样品的测定结果表明:六六六(1.82～3.70μg/kg)和六氯苯(0.94～9.8μg/kg)有少量检出,滴滴涕的检出率高达100%,其含量范围较宽(1.08～308.76μg/kg),平均值为53.28μg/kg,其中85%的样品中滴滴涕含量/(滴滴伊+滴滴滴)含量的比值小于1,表明滴滴涕主要来自于早期的使用。

A method was developed for the determination of organochlorine pesticides（OCPs）in soils using accelerated solvent extraction（ASE,Florisil cleanup in the extraction cell）and gel permeation chromatography（GPC）on-line concentration prior to the determination by gas chromatography-triple quadrupole tandem mass spectrometry（GC-MS/MS）.And then 20 agricultural soil samples in Shanghai suburbs were determined.Multiple reaction monitoring（MRM）was applied to qualify and quantify the target compounds.In the different linear ranges（included in 0.001-0.2 mg/L）of each pesticide,the correlation coefficients were higher than 0.995.The average recoveries in spiked soils were 65.9%-140.0% with the relative standard deviations of 1.5%-20.3%（n=5）.The limits of detection（LOD）（S/N=3）for these pesticides were from 0.1 to 3.0 μg/kg and the limits of quantification（LOQ）（S/N=10）were from 0.3 to 8.0 μg/kg.Among these soils,hexachlorocyclohexane（HCHs）and hexachlorobenzene（HCB）were detected little with a content ranges of 1.82-3.70 and 0.94-9.8 μg/kg,respectively.DDTs（including 2-（2-chlorophenyl）-2-（4-chloropenyl）-1,1,1-trichloroethane（p,p＇-DDT）,2,2-bis（4-chlorophenyl）-1,1-dichloro-ethylene（p,p＇-DDE）,2,2-bis（4-chlorophenyl）-1,1-dichloroethane（p,p＇-DDD））were found widely with a range of 1.08-308.76 μg/kg and mean value of 53.28 μg/kg.The content ratio of DDT/（DDE＋DDD）were less than 1.0 in 85% soil samples,indicating that DDT might come from the early days.