Analysis of pesticides in fruits by pressurized liquid extraction and liquid chromatography-ion trap-triple stage mass spectrometry

A multi-residue method using pressurized liquid extraction (PLE) and liquid chromatography-quadrupole ion trap-triple stage mass spectrometry (LC-IT-MS3) has been developed for determining trace levels of pesticides in fruits. The selected pesticides can be distinguished in: benzimidazoles and azoles, organophosphorus, carbamates, neonicotinoids, and acaricides. PLE has been optimized to extract these pesticide residues from oranges and peaches by studying the effect of experimental variables on PLE efficiency. Samples were extracted at high temperature and pressure (75 degrees C and 1500 psi) using ethyl acetate as extraction solvent and acidic alumina as drying agent. The recoveries obtained by PLE ranged from 58% to 97% and the relative standard deviation (RSDs) from 5% to 19%. The limits of quantification (LOQs) of the compounds were from 0.025 to 0.25 mg kg(-1), which are well-below the maximum residue limits (MRLs) established by the European Union (EU) and the Spanish legislations. (c) 2005 Elsevier B.V. All rights reserved.