Therefore, sensitive and reliable methodologies have been developed for the analysis of each group of residues separately. The determination of pesticides in feed has been
based on Soxhlet, pressurised liquid extraction(PLE), matrix solid-phase dispersion (MSPD) or QuEChERS. Some of these procedures have been followed by a clean-up step based on solid-phase extraction(SPE)or dispersive SPE (d-SPE), and subsequent chromatographic analysis by gas chromatography (GC) coupled to electron capture detection (ECD), mass spectrometry (MS)or tandem mass spectrometry(MS/MS)