Abstract: 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.

Key words: multiple reaction monitoring (MRM), organochlorine pesticides (OCPs), soils , gas chromatography-tandem mass spectrometry (GC-MS/MS)