Rapid determination of organophosphorous pesticides in leeks by gas chromatography-triple quadrupole mass spectrometry

A rapid multi-residue method was developed for the determination of 20 organophosphorous pesticide residues in leeks by gas chromatography coupled to triple quadrupole mass spectrometry (GC-QqQ-MS/MS). The method was based on the modified QuEChERS sample preparation method. After microwave pre-treatment, leek samples were extracted with acetonitrile containing acetic acid 0.1% and cleaned by dispersive solid phase extraction. The QqQ analyser acquired data in selected reaction monitoring (SRM) mode. Recoveries of 20 organophosphorous pesticides ranged from 81.0% to 109.4% with the relative standard deviations (RSD) below 10.4%. The limits of detection (LODs) were 0.07-1.5 mu g/kg. The limits of quantitation (LOQs) ranged from 0.25 to 5 mu g/kg. Ten leek samples were analysed for method application. (C) 2010 Elsevier Ltd. All rights reserved.