Single-laboratory validation and uncertainty analysis of 82 pesticides determined in pomegranate, apple, and orange by ethyl acetate extraction and liquid chromatography/tandem mass spectrometry.

Single-laboratory validation results are reported for the multiresidue determination of 82 pesticides at < or = 10 ng/g levels in pomegranate, apple, and orange. Samples were extracted with ethyl acetate, and the extracts were cleaned up by dispersive solid-phase extraction with primary secondary amine sorbent. The concentrations of the pesticides were estimated within 18 min of chromatographic run time by liquid chromatography/mass spectrometry with multiple-reaction monitoring. The method was reproducible (HorRat of < 0.5 at 10 ng/g) with measurement uncertainties of < 15% for all the compounds at 10 nglg in all 3 matrixes. The limits of quantitation ranged from 2.5 to 5.0 ng/g with recoveries of 70-120% for most pesticides. Matrix-induced signal suppressions were significantly higher in orange compared with those in pomegranate and apple. The method offers a less expensive and safer alternative to the existing multiresidue analysis methods for fruits and vegetables.