气相色谱-串联质谱法测定土壤中的有机氯农药

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0.001～2 mg/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0.1～3.0 μg/kg,定量限（S/N=10）为0.3～8.0 μg/kg。实际土壤样品的测定结果表明：六六六(1.82～3.70 μg/kg)和六氯苯(0.94～9.8 μg/kg)有少量检出,滴滴涕的检出率高达100%,其含量范围较宽(1.08～308.76 μg/kg),平均值为53.28 μg/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

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

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.