Abstract: An ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the simultaneous quantitative determination of fipronil and its metabolites in whole egg powder, egg yolk powder and dairy products was developed. Samples were extracted with acetonitrile and saturated sodium chloride solution was added to separate the organic and aqueous phases. The supernatant after low-temperature precipitation of protein was applied onto an HLB solid-phase extraction cartridge for purification. The chromatographic separation was accomplished with an Acquity UPLC BEH C18 column (2.1 mm × 50 mm, 1.7 μm) using gradient elution with a mobile phase consisting of a mixture of acetonitrile and water. The analytes were detected using a negative electrospray ion source under the multiple reaction monitoring mode and quantitated by the external standard method. The results demonstrated that the linear ranges were from 0.5 to 20.0 μg/L with good correlation coefficients (R2 > 0.990). The limit of detection and the limit of quantitation were 0.2 and 1.0 μg/kg for all analytes, respectively. The recoveries of fipronil and its metabolites in different matrixes at spiked concentration levels of 1, 2, 4 and 20 μg/kg varied from 63.4% to 118.7%, with relative standard deviations between 0.7% and 10.3%. The method proved to besensitive, accurate and suitable for the rapid quantification of fipronil, fipronil sulfide, fipronil sulfone and fipronil desulfinyl in protein-rich foods.

Key words: ultra performance liquid chromatography-tandem mass spectrometry; fipronil; whole egg powder; egg yolk powder; dairy products

摘要： 建立超高效液相色谱-串联质谱法测定全蛋粉、蛋黄粉及乳制品中氟虫腈及其代谢物的通用检测方法。样品经乙腈提取，饱和氯化钠使乙腈和水分层，低温冷冻沉淀蛋白质，取上清液转移至HLB固相萃取小柱净化，Acquity UPLC BEH C18色谱柱（2.1 mm×50 mm，1.7 μm）分离，以水-乙腈为流动相进行梯度洗脱，电喷雾离子源负离子模式、多反应监测模式测定，外标法定量。结果表明：氟虫腈及其代谢物在0.5～20.0 μg/L质量浓度范围内线性关系良好，R2均大于0.990；检出限均为0.2 μg/kg，定量

关键词: 超高效液相色谱-串联质谱；氟虫腈；全蛋粉；蛋黄粉；乳制品