Multiresidue method for the control of pesticide residues in tomatoes and derived products

Abstract

A new multiresidue method, intended for the routine analysis of 60 multi-class pesticides in tomatoes and derived products, has been developed. The method uses gas chromatography, with a large volume injection system and tandem mass spectrometry detection (LVI-GC-MS-MS). The pretreatment of the samples is fast and simple, as the pesticide residues are extracted from the sample with ethyl acetate in presence of NaHCO₃ and anhydrous Na₂SO₄, without additional clean-up steps and, consequently, with cost and time saving benefits. The method presents appropriate selectivity and good sensitivity with limits of quantification (LOQs) between 0.5 and 20 μg kg⁻¹, which are lower than the maximum residue levels established by several regulatory legislation. Average recoveries between 70 and 115%, with a relative standard deviation lower than 20% in all cases, and good linearity were obtained in the studied concentration range. For the routine analysis, a quality control system was applied to avoid false positive and false negative results.