Evaluation of cost-effective methods in the pesticide residue analysis of non-fatty baby foods

Three non-fatty ready-to-eat baby food matrices (fruits: juice, puree and cocktail plus rice flour/starch and sugar) were fortified with 0.01, 0.05, 0.1 and 0.2 mg/kg of dimethoate, chlorpyrifos, methidathion, phosalone and diazinon. Simple methods including extraction by ethyl acetate [EtAc] and acetone partition and determination by gas chromatography with Nitrogen-Phosphorus Detector (GC-NPD) were used. Acceptable pesticides recoveries (70-110%), low detection and quantification limits (0.001 to >0.1 mg/kg and 0.005 to 0.04 mg/kg, respectively) and repeatabilities (%RSDs), in 0.01 mg/kg, within 2.9-13.9% were observed. However, analytes recoveries were affected (p < 0.05) by both the baby food formulation and the extraction method used. Specifically, fruits puree and cocktail EtAc extracts gave excessively over-(dimethoate recoveries of 119.7-153.5%) or underestimation (phosalone and especially diazinon recoveries of 19.3-79.2%) in contrast to fruits juice (e.g., 61.3-87.9%). Also, EtAc extracts showed higher amount of lipophilic compounds and provided lower recoveries for non-polar analytes than those of acetone partition. Consequently, the examined methods may be successfully applied in non-fatty baby foods with the matrix-matched standards determination, following improvements of certain parameters in relation to the clean-up of samples. (C) 2009 Elsevier Ltd. All rights reserved.