Determination of 16 Kinds of Organochlorine and Pyrethroid Pesticide Residues in Nuts by Gas Chromatography

The purpose of this paper is to establish an analytical method for the determination of 16 organochlorine and pyrethroid pesticide residues in nuts by gas chromatography (GC). The samples were extracted by acetone:hexane (3:7, V:V), purified by 0.2 mL concentrated sulfuric acid sulfonation, and the organochlorines and pyrethroids were separated by a DB-17MS column (30 m×0.32 mm, 0.25 μm), and quantified by gas chromatography-electron capture detector (GC-ECD). The results showed that the organochlorine and pyrethroid pesticides showed good linearity in the concentration range of 0.01~0.20 μg/mL and the corresponding peak areas. The determination coefficients (r²) were above 0.996, and the limits of detection were 0.1~0.4 μg/kg. In this study, the spiked recovery experiments were also performed on samples of different matrices (pistachios, macadamia nuts, cashew nuts, pistachios, walnuts, and padanuts) at low (10 μg/kg), medium (40 μg/kg), and high (100 μg/kg) concentrations, respectively. The extraction rates ranged from 81.6% to 119.5% with the relative standard deviations (RSDs) of 1.03%~5.36%. The method is simple, accurate, reproducible and suitable for the determination of 16 organochlorine and pyrethroid pesticide residues in nuts.