Development and verification for analysis of pesticides in eggs and egg products using QuEChERS and LC-MS/MS

QuEChERS method was applied and validated for the multi-residue analysis of pesticides in eggs and egg products. The method includes extraction with buffered acetonitrile and clean-up with dispersive sorbents, followed by LC-MS/MS analysis. The validation parameters were used based on the guideline of SANCO/12495/2011. Recoveries were within the range of 71-108%, and the relative standard deviations were 2-13% at the 3 different concentrations evaluated for eggs and egg products. The limits of quantification for the target compounds ranged from 0.3 to 6 ng/g. Monitoring of 100 domestic eggs and 50 imported egg products were performed to verify the adaptability in real samples. No samples contained residues exceeding the maximum residue limit (MRL). Carbendazim, dimethoate, and pirimicarb were each found in egg yolks at the level of 2 ng/g, in the same sample, well below their MRLs of 50-100 ng/g.