Simultaneous determination of 56 organochlorine and pyrethroid pesticides in traditional Chinese medicines by GC coupled with dual-tower and dual-column

The paper is to report the establishment of a method for the determination of multi-residue    organochlorine and pyrethroid pesticides in traditional Chinese medicines (TCMs).  Fifty-six pesticides were extracted by high-speed homogenization, and then purified through gel permeation chromatography (GPC) and solid phase extraction (SPE) cartridges.  The residues were simultaneously identified and quantified by GC-ECD equipped with dual tower, dual column and two μ-ECD detectors.  The analytical performance was demonstrated by the analysis of 3 TCMs samples’ extracts, spiked at three concentration levels for each pesticide.  In general, the recoveries ranging from 70% to 110%, with relative standard deviations (RSDs) better than 15%, were obtained.  The limit of detection (LOD) for most of the targeted pesticides tested was below 0.01 mg·kg⁻¹.  The method had good extraction efficiency, purification effect and good reproducibility, which could be applied to the determination of organochlorine and pyrethroid pesticide residues in the routine analysis of TCMs.