Abstract
A simple method for the determination of 13 representative pesticides in 9 Chinese herds employing modified QuEChERS(Quick,Easy,Cheap,Effective,Rugged and Safe) followed by gas chromatography-tandem mass spectrometric(GC-MS) analysis was developed.For the fresh or dry samples,the pesticides were extracted by acetonitrile or acetonitrile-H2O,respectively,and then liquid-liquid partitioning formed by adding anhydrous MgSO4 and NaCl;followed by a simple cleanup step using multi-walled carbon nanotubes(MWCNTs) for fresh samples extraction,and using MWCNTs and PSA(primary secondary amine) for dry samples extraction as dispersive solid phase extraction(d-SPE).The aliquot was confirmed and determined by gas chromatography with selected ion monitoring mode(SIM)-mass spectrometry.The recoveries for all the pesticides studied were from 67.9% to 100.3% with relative standard deviation(RSD) from 0.6% to 11.0% in the concentration range of 0.02-0.4 mg/kg.The limit of quantitation(LOQ) was from 0.004 mg/kg to 0.03 mg/kg,and the limit of detection(LOD) was from 0.009 mg/kg to 0.01 mg/kg.Three positive market samples,polluted by target pesticides,were screened by the developed method.
Published Version
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