稳定同位素稀释超高效液相色谱-串联质谱法测定饲料中氟虫腈及其代谢物

Determination of fipronil and its metabolites in feeds by stable isotope dilution ultra high performance liquid chromatography-tandem mass spectrometry

建立了超高效液相色谱-串联质谱测定饲料中氟虫腈及其代谢物氟甲腈、氟虫腈硫醚和氟虫腈砜的方法。样品经纯水和乙腈超声提取后加入氯化钠盐析,采用Qu ECh ERS技术净化,以Waters HSS T3 C18色谱柱分离,甲醇和纯水为流动相进行梯度洗脱,在多反应监测、负离子模式下进行检测,内标法定量。氟虫腈及其代谢物在各自的范围内呈良好的线性关系,相关系数均大于0.999 8;氟虫腈及其代谢物的检出限和定量限分别为0.05μg/kg和0.2μg/kg,加标回收率为92.3%~105.4%,相对标准偏差为0.9%~2.3%(n=5)。该法样品前处理过程简单,净化效果好,灵敏度高,适用于各种饲料中氟虫腈及其代谢物含量的测定。

A method based on ultra high performance liquid chromatography-tandem mass spectrometry（UHPLC-MS/MS） was established for the determination of fipronil and its metabolites in feeds. Sodium chloride was added to the samples after the ultrasonic extraction of pure water and acetonitrile,and then cleaned up by the QuEChERS method. The target analytes were separated on a Waters HSS T3 C18 column using methanol and water as mobile phases with gradient elution,and detected by a MS/MS system under negative electro-spry ionization（ESI-） and the multiple reaction monitoring（MRM） mode. The limits of detection（LODs） were 0. 05 μg/kg,and the limits of quantification（LOQs） were 0. 2 μg/kg.The linear correlation coefficients were more than 0. 999 8. The average recoveries ranged from 92. 3% to105. 4% with RSDs no more than 2. 3%. This method is suitable for the identification of fipronil and its metabolites in feeds because of its simplicity and high sensitivity.