Determination of organochlorine pesticides in horticultural samples by microwave assisted extraction followed by GC-ECD

A method to determine 21 organochlorine pesticides in horticultural samples (lettuce, pepper, tomato, spinach and potato) based oil microwave assisted extraction (MAE) followed by solid-phase extraction (SPE) clean-up is described. After extraction with hexane: acetone (50: 50), it carbon cartridge was employed for the clean-up step. Pesticides were eluted with 5 mL of hexane:ethyl acetate (80:20) and determined by gas chromatography and electron capture detection (GC-ECD). Results were confirmed by GC-MS analysis. Analytical recoveries obtained were ca. 100% for most of the Studied pesticides with the proposed method in each analysed matrix. The method was applied to analyse 35 commercial samples from A Coruna (NW Spain); only two samples contained pesticide residues, but none Of them exceeded the MRLs established by EU legislation.