A multi-residue method is described that eliminates the need for a clean-up step and thus allows the rapid determination of pesticides in crude extracts of lettuce. Samples were extracted with a mixture of ethyl acetate, Na2SO4 and NaHCO3 and the crude extracts analysed directly using large volume–difficult matrix introduction (LV-DMI) in combination with gas chromatography–time of flight–mass spectrometry (GC-TOF-MS). The LV-DMI procedure described was evaluated for the analysis of dimethoate, pyrimethanil, chlorothalonil, vinclozolin, furalaxyl and oxadixyl. Satisfactory response was obtained at the lowest calibrated level (LCL) of 0.0025 µg ml−1, with good linearity over the range 0.0025–0.5 µg ml−1
(0.005–1.0 mg kg−1 equivalent). Average recoveries between 73 and 118% were obtained at the 0.01–0.5 mg kg−1 levels with RSD values ≤13%.
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