Alternative QuEChERS-based modular approach for pesticide residue analysis in food of animal origin.

The approach for pesticide residue analysis in food of animal origin differs strongly from the one established for food of plant origin, as laboratories mainly focus on conventional methods for the analysis of non-polar pesticides known to accumulate in fatty tissues. However, these group-specific methods are very laborious and cost intensive and typically require extraction of fat components followed by extensive clean-up steps to remove matrix constituents. This work highlights the development and validation of a straightforward QuEChERS-derived clean-up procedure enabling facile, precise, and reliable identification and quantitation of pesticide residues in food of animal origin, which can be extended to various other commodities with moderate fat content and applied to replace traditional group-specific methods. Two additional methods for lean and highly fatty commodities complete this well-established "simplified modular system". The proposed method was in-house validated in terms of accuracy and precision, recovery and linearity as well as specificity and sensitivity on two representative commodities for food of animal origin (egg and meat). For the majority of the more than 80 pesticides investigated, satisfactory results were obtained. Procedural matrix calibration was applied for screening purposes in conjunction with GC-MS/MS or LC-MS/MS as integral part of the approach. Apparent recoveries for most of the compounds ranged from 70 to 120 % (RSD < 20%) at spiking levels of 0.01 (LOQ level) and 0.05 mg/kg. Accuracy of the method has been demonstrated by application to reference material from previous EU proficiency tests. Only in case of positive screening results a standard addition approach was applied for precise quantitation.