Determination of 24 Organochlorine Pesticides and Pyrethroids in Complex Matrix Soils by Comprehensive Two-dimensional Gas Chromatography with Micro-electron Capture Detector
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ABSTRACT
BACKGROUNDCurrently the analysis methods of organochlorine pesticides and pyrethroids in environment samples are gas chromatography and gas chromatography-mass spectrometry (GC-MS). Gas chromatography with electron capture detector has been widely used in the study of environmental behavior of pollutants due to its high sensitivity. GC-MS has good qualitative results, but the detection sensitivity is relatively low.OBJECTIVESTo establish an easy, highly efficient and precise method for determination of 20 organochlorine pesticides and 4 pyrethroids in complicated matrix soils.METHODSThe residues of organochlorine pesticides and pyrethroids in samples from Jiangsu Province in 2018 were studied. In order to improve the qualitative accuracy and ensure the detection sensitivity, a comprehensive two-dimensional gas chromatography-electron capture detector detection method for determination of 20 organochlorine pesticides and 4 pyrethroids in complex-matrix soils was established. TG-35MS column (30m×0.25mm×0.25μm) was chosen as the column for the first dimension, and a DB-1 column (0.8m×0.18mm×0.18μm) was chosen as the column for the second dimension. The fresh sample was mixed with anhydrous sodium sulfate and extracted with hexane-acetone (1:1, V/V), subsequently purified by activated sheet copper. The analysis was conducted by GC×GC-μECD, qualified by retention time and quantified by external standard.RESULTSThe proposed method showed good linearity with correlation coefficients (r) higher than 0.995 in the concentration range of 1.0-500μg/L, with the detection limits of 0.02-0.17μg/kg. The recovery of standard addition method ranged from 80.7% to 103.5%, and the relative standard deviations (n=6) were 1.84%-10.12%.CONCLUSIONSThe proposed method combined high sensitivity detector with comprehensive two-dimension gas chromatography overcomes the matrix interference in complex sample, which shows a good detection sensitivity and peak capacity. The detection limit of the method is far lower than that of HJ 835-2017 standard (0.02-0.09). This method can provide reference for the analysis of multiple organochlorine pesticides and pyrethroids in complex-matrix soil.
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