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

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 microg 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.