Pesticide multiresidue analysis of peanuts using automated gel permeation chromatography clean-up/gas chromatography-mass spectrometry

Abstract

A method based on automated gel permeation chromatography (GPC) and on-line quantitative concentration was developed for the determination of residues of 38 typically used pesticides in high-oil peanuts. Pesticides were extracted using acetonitrile into an oil fraction containing little of the peanut matrix. After changing the solvent to the mobile phase (1 : 1 cyclohexane : ethyl acetate), clean-up was carried out using GPC, the final collected solution being automatically concentrated to a fixed volume and transferred into vials for gas chromatography (GC) injection. The pesticides were analysed by gas chromatography-mass spectrometry (GC/MS) in the selected ion monitoring (SIM) mode. Average recoveries (spiked levels of 0.02, 0.05, and 0.1 µg g⁻¹) were between 70 and 117%. The relative standard deviation of the method was 3.5–21% (n = 6). This approach gave comparable results with a previously published method.

Keywords:

• gel permeation chromatography (GPC)
• clean-up
• pesticide residues
• gas chromatography-mass spectrometry (GC/MS)
• peanuts

Acknowledgements

The authors are grateful to Dr Steven Lehotay (USDA, Agricultural Research Service, USA) for help in suggestions and revising the manuscript. Thanks are also given to two referees and the editor.