Application of gas chromatography-triple quadrupole mass spectrometry in the quantification-confirmation of pesticides and polychlorinated biphenyls in eggs at trace levels

A new multiresidue method has been developed and validated for the simultaneous analysis of 57 compounds, including organochlorine and organophosphorus pesticide residues (OCPs and OPPs) and polychlorinated biphenyls (PCBs), in eggs at trace levels by gas chromatography coupled to triple quadrupole mass spectrometry (GC-QqQ-MS/MS). Egg samples were extracted by a simple and fast matrix solid phase dispersion (MSPD) procedure using C18 as sorbent, and ethyl acetate and acetonitrile saturated in n-hexane (85:15, v/v) as elution solvent with a simultaneous clean up with Florisil in-line. The QqQ analyzer acquired data in selected reaction monitoring (SRM) mode, permitting both quantification and confirmation in a single injection with a running time reduced up to 17.70 min. Recovery was in the range of 70–110% and 70–106% at 15 and 50 μg/kg, respectively. Precision values expressed as relative standard deviation (RSD) were lower than 20%. Linearity in the range of 10–150 μg/kg provided determination coefficients (R2) higher than 0.98 for all compounds. Limits of detection (LODs) for pesticides were ≤2.25 μg/kg and limits of quantification (LOQs) ranged from 0.02 to 7.78 μg/kg. LODs for PCBs were ≤0.41 μg/kg and LOQ were ≤0.71 μg/kg. The method was applied to real samples. Endosulfan sulphate and p,p′-DDE were found in two samples at concentrations below the first calibration level.