A method was established for the simultaneous determination of fipronil and its metabolites in eggs by gas chromatography-tandem mass spectrometry coupled with QuEChERS. Fipronil and its metabolites were extracted from eggs with acetonitrile, and the solution was dehydrated with 150 mg anhydrous magnesium sulfate. The extracts were purified with 50 mg N-propyl ethylenediamine (PSA) and 50 mg C18, and a capillary column pesticide Ⅱ was used. The analytes were detected in timed selected reaction monitoring (timed-SRM) mode, and were quantified using external standard method with matrix correction standard curves. A good linearity in the range of 1.0-200 μg/L with correlation coefficients (R2)>0.999 was observed. The limits of quantification (LOQs) were between 0.5 and 1.0 μg/kg. The recoveries at three spiked levels (2.0, 5.0 and 10.0 μg/kg) were in the range of 87.8% to 111.5% with RSDs between 2.0% and 9.2% (n=3). This new method satisfied the related regulations of the European Union for the determination of fipronil and its metabolites in eggs.
Keywords: QuEChERS; eggs; fipronil and its metabolites; gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS).