Analysis of 140 pesticides from conventional farming foodstuff samples after extraction with the modified QuECheRS method C. Lesueur a,b, * , P. Knittl a , M. Gartner a , A. Mentler c , M. Fuerhacker b a Gartner & LVA GmbH, Blaasstrasse 29, 1190 Vienna, Austria b BOKU-University of Natural Resources and Applied Life Sciences, Institute of Sanitary Engineering and Water Pollution Control, Muthgasse 18, 1190 Vienna, Austria c BOKU-University of Natural Resources and Applied Life Sciences, Institute of Soil Research, Peter Jordanstrasse 82, 1190 Vienna, Austria Received 10 July 2007; received in revised form 28 August 2007; accepted 11 September 2007 Abstract Pesticides in foodstuff are becoming a major issue due to their intensive use in agriculture. Thus an appropriate control of their res- idues in food samples has to be operated. In this study we analysed 105 pesticides with GC/SQ-MS and 46 pesticides with HPLC/IT-MS after extraction with the QuECheRS method in four matrices (grape, lemon, onion and tomatoes). For GC-amenable substances, the LOD and LOQ ranged from 0.4 to 48.2 lg/kg and from 1.2 to161 lg/kg, respectively. For HPLC-amenable substances, they varied from 1.0 to 115 lg/kg and from 3.3 to 382 lg/kg, respectively. With GC/MS, 61–82% of the substances showed a recovery in the range of 70– 110% and 6–30 % presented a recovery higher than 110% at the 500 lg/kg fortification level. With HPLC/MS, 87–93% of the substances presented recoveries in the range of 70–110% at the 500 lg/kg fortification level compared to 78–85% at the 50 lg/kg fortification level. Lemon and onion showed poor recoveries but are known to be difficult matrices (high acidic and high sulfur content, respectively). The method was proved to be repeatable with RSD lower than 20% at 500 lg/kg and lower than 15% at 50 lg/kg with both devices. Ó 2007 Elsevier Ltd. All rights reserved. Keywords: Gas chromatography; Liquid chromatography; Mass spectrometry; Pesticide residues; Foodstuff 1. Introduction More and more different pesticides are used nowadays in agriculture. Since pesticides are potentially harmful to the environment and consequently to human beings through the consumption of pesticide contaminated food and water, the European Community established maximum residue levels (MRLs), based on the assumption that good agricultural practice is applied at the use of pesticides in farming, for pesticide residues in water (Commission of the European Communities, 2000) and foodstuff (Commis- sion of the European Communities, 1990). As a consequence food commodities have to be con- trolled to assure the non-violation of the MRLs. For apo- lar and middle polar pesticides, the detection of pesticide residues is commonly achieved through analysis with gas chromatography (GC) coupled to single quadropole (SQ) and, less frequently, triple quadropole (QQQ) mass spec- trometers (MS) after extraction according to the DIN Norm 12393 parts 1–3 (DIN EN 12393, 1998) adapted from the German Norm DFG S19 (DFG-Methode S19, 1999) or according to the Luke Method (Luke, Froberg, Doose, & Masumato, 1981) and more recently according to the (modified) QuECheRS (standing for ‘‘Quick, Easy, Rugged and Safe’’) method (Anastassiades & Lehotay, 2003) drafted as European Norm (CEN/TC 275 & Draft, 2006). The analysis of foodstuff with GC/MS has already been successfully implemented in numerous laboratories for the determination of pesticide multiresidues in food samples (Dı ´ez, Traag, Zommer, Marinero, & Atienza, 0956-7135/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodcont.2007.09.002 * Corresponding author. Address: BOKU-University of Natural Re- sources and Applied Life Sciences, Institute of Sanitary Engineering and Water Pollution Control, Muthgasse 18, 1190 Vienna, Austria. Tel.: +43 1 36885 5574; fax: +43 1 36885 5520. E-mail address: celine.lesueur@boku.ac.at (C. Lesueur). www.elsevier.com/locate/foodcont Available online at www.sciencedirect.com Food Control 19 (2008) 906–914