液相色谱-串联质谱法测定蛋及蛋制品中氟虫腈及其代谢物的残留量

Determination of Fipronil and Its Metabolites in Egg and Egg Products by Liquid Chromatography-Tandem Mass Spectrometry

建立了液相色谱-串联质谱测定蛋及蛋制品中氟虫腈及其代谢产物的分析方法。样品经酸性乙腈提取,QuEChERS法净化,XDB-C_(18)色谱柱(50 mm×4.6 mm,1.8μm)分离,并以含0.1%(v/v)甲酸的5 mmol/L乙酸铵水溶液-含0.1%(v/v)甲酸的乙腈溶液为流动相,梯度洗脱,电喷雾负离子模式电离,多反应监测模式检测,基质匹配外标法定量。结果表明氟虫腈及其代谢物在0.2~10μg/L范围内线性关系良好,相关系数(r2)均大于0.99。方法检出限(S/N>3)和定量限(S/N>10)分别为0.2μg/kg和2μg/kg。在不同基质中,氟虫腈及其代谢物在2、5、20μg/kg的添加水平下平均加标回收率为74.6%~113%,相对标准标准偏差为2.21%~14.0%(n=6)。该方法有效补偿了液相色谱-串联质谱检测过程中的离子化抑制效应,灵敏度和准确度高,适用于鸡蛋、鸡肉、鸡内脏、鸡蛋面、蛋糕和蛋黄酱中氟虫腈、氟虫腈砜、氟虫腈亚砜和氟甲腈的测定。

A liquid chromatography-tandem mass spectrometry （LC-MS/MS） was established for the determination of fipronil its metabolites in egg and egg products. The samples were extracted with acid-acetonitrile,cleaned up by QuEChERS method. The separation was performed on an XDB-C18 column （50min×4.6 mm, 1.8μm） with the mobile phases of 5 mmol/L ammonium acetate aqueous solution containing 0.1% （v/v） formic acid and acetonitrile containing 0.1% （v/v） formic acid. The identification and quantitation of fipronil and its metabolites were performed by MS/MS in negative electrospray ionization （ESI-） and multiple reaction monitoring （MRM） mode. The quantitative analysis was carried out by external standard method. A good linear relationship,with the correlation coefficient （r2） greater than 0.99, was found in the mass concentration range of 0.2-10 μg/L. The limit of detection （LOD,S/N〉3） and limit of quantitation （LOQ,S/N〉10） were 0.2 μg/kg and 2μg/kg respectively. The recoveries of fipronil and its metabolites in different matrixes spiked with 2,5,20 μg,/kg varied from 74.6% to 113% ,and the relative standard deviations （RSDs） were between 2.21% and 14.4% （n=6）. The method can effectively correct the ionization suppression,and it is sensitive,accurate and suitable for the monitoring of fipronil,fipronil sulfide, fipronil sulfone and fiponil desulfinyl in egg,chicken,chicken entrails,egg noodle,cake and mayonnaise.