Abstract
The search on pyridalyl residues, the novel insecticide, in strawberries and spring onions was evaluated. The QuEChERS technique was used for sample preparation. A fast gas chromatography-mass spectrometry (GC-MS) method was developed and validated for the analysis of pyridalyl in both matrices. Fast GC-MS was performed with a narrow-bore capillary column and a quadrupole mass detector with electron ionization and negative chemical ionization, both operating in selected ion monitoring mode. Fortification studies at 1, 5, 10, and 250 mu g/kg for fruit and vegetable matrices were performed. Recoveries for all fortification levels, two ionization modes ranged from 72 to 114 %. Matrix effects were discussed. Limits of quantification were established at 1 mu g/kg. Field experiments to investigate the pre-harvest interval were carried out. The proposed method was applied successfully to the determination of pyridalyl residues in samples available on Slovak market, and none of the samples contained detectable amounts of pesticides. The developed method is simple, efficient, and easy to adopt in laboratories engaged in pesticide residue analysis method.