Abstract: A method was developed for the determination of organochlorine pesticide (OCP) residues in soil/sediment using high resolution gas chromatography coupled with low resolution mass spectrometry. The analytical procedures consisted of Soxhlet extraction, sulfur removal 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 (SIM) 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 compound solutions ranged from 60% to 110% and from 1.5% to 18%, respectively. The limits of detection ranged from 0.20 to 10.3 μg/kg were established for the 23 OCPs. The method showed 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: organochlorine pesticides (OCPs), sediment , soil, isotope dilution gas chromatography-mass spectrometry (ID-GC-MS)