Determination of fungicide residues in baby food by liquid chromatography-ion trap tandem mass spectrometry

Current European Commission Directives on foods for infants and young children places emphasis on the control of pesticide residues at levels below 10 mu g kg(-1). In the present work, a liquid chromatography electrospray ionisation ion trap tandem mass spectrometry (LC-Ion Trap-MS/MS) has been developed for the multiresidue of 10 multiclass fungicides (carbendazim, thiabendazole, imazalil, tridemorph, triadimefon, bitertanol, prochloraz, flutriafol, myclobutanil and diphenylamine) in fruit-based baby food. The developed method is based on a simple sample treatment (QuEChERS), which consists of a liquid-liquid extraction using acetonitrile, followed by a clean-up step based on dispersive solid-phase extraction with primary secondary amine (PSA). Subsequent identification and quantitation was accomplished by liquid chromatography/electrospray tandem mass spectrometry using an ion-trap mass spectrometer in the product ion scan MS/MS mode. Matrix effects were evaluated in LC-MS and LC-MS/MS mode experiments, obtaining a reduction of these effects when working in MS/MS mode for most of the analytes. Limits of detection (LOD) were between 0.5 and 3.0 mu g kg(-1) depending on the pesticide studied, all being within European Union regulations for baby food. Finally, the proposed method was applied to 25 baby food samples obtained from local supermarkets. Imazalil, thiabendazole and carbendazim were detected in the studied samples. However, none of the samples tested were found to be upper the EU standard. (C) 2012 Elsevier Ltd. All rights reserved.