Rapid method for the determination of 16 organochlorine pesticides in sesame seeds by microwave-assisted extraction and analysis of extracts by gas chromatography–mass spectrometry

A method for the multiresidue analysis of 16 organochlorine insecticides in sesame seeds has been developed. The method is based on the microwave-assisted extraction (MAE) of the sesame seeds by the use of a water–acetonitrile mixture followed by Florisil clean-up of the extracts and subsequent analysis by gas chromatography–mass spectrometry (GC/MS) in the selected ion monitoring (SIM) mode. MAE operational parameters (extraction solvent, temperature and time, extractant volume) were optimized with respect to extraction efficiency of the target compounds from sesame seeds with 46% oil content. Recoveries >80% with relative standard deviations (RSD) <12% were obtained for all compounds under the selected parameters. The Florisil clean-up step proved sufficient for the removal of co-extracted substances so that no adverse effect on the chromatographic system was observed. Limit of quantification (LOQ) values were in the range of 5–10 μg/kg. The proposed method was applied in the analysis of sesame seed samples imported to Greece.