Development of precise GC-EI-MS method to determine the residual fipronil and its metabolites in chicken egg

•First GC-EI-MS method to determinate fipronil and its metabolites in chicken egg.•Signal intensity of analyte and TIC of sample were evaluated simultaneously.•Oxidation was the main metabolism pathway of fipronil in chicken egg. Fipronil is a highly toxic insecticide, and fipronil egg scandal greatly threaten people’s health. Herein, a precise and reliable method was developed for the determination of fipronil and three metabolites in chicken egg by GC-EI-MS. Sample pretreatment took about 20 min and baseline separation of four analytes were realized within 12 min by GC–MS. Moreover, the limits of detection were 0.2–0.5 ng g−1 and the limits of quantitation was 0.5–1 ng g−1 with relative standard deviations (RSDs) lower that 3.32%. Satisfactory recoveries were get in the range of 81.16–103.57% for three levels of spiked samples. Finally, the developed method has been applied for the analysis of egg samples from four sources. Results showed that fipronil and fipronil-sulfone were detected in three samples, while fipronil-desulfinyl and fipronil-sulfide were totally absent. The method showed great promising in quantification of fipronil and its metabolites in food safety affairs.