Determination of residual pesticides in processed foods manufactured from livestock foods and seafoods using ion trap GC/MS

Abstract

A simultaneous method using iontrap gas chromatography/mass spectrometry (GC/MS) was developed for the determination of pesticide residues in four processed foods (frozen Chinese dumpling, eel kabayaki, corned beef and retort curry). Pesticide residues were extracted from samples with ethyl acetate-cyclohexane (1:1) in the presence of anhydrous sodium sulfate. The extract was concentrated and the residue was dissolved in n-hexane. The lipids in the extract were removed by acetonitrile-n-hexane partitioning, following which the acetonitrile layer was cleaned up using a C18 mini-cartridge column and a graphite carbon/PSA silica (GCB/PSA) mini-cartridge column. The limits of quantification of compounds in 4 processed foods were below 0.01 μg/g. The recoveries of 292 compounds spiked at 0.1 μg/g in 4 kinds of processed foods, and 210 to 262 pesticides showed acceptable recoveries of 70-120% with low repeatability (15%) and intermediate precision (<20%) only at the 0.1 μg/g spiked level. This method is expected to be useful for multi-residue analysis of pesticide residues in processed foods manufactured using livestock and seafoods as the main raw materials.