气相色谱-负化学源质谱法测定牛奶中氟虫腈及其代谢物残留

Determination of fipronil and its metabolites in milk by gas chromatographynegative chemical ionization mass spectrometry

建立了气相色谱-负化学源质谱(GC-NCI-MS)测定牛奶中氟虫腈及其3种代谢物残留量的分析方法。牛奶经乙腈提取后,分散固相萃取技术QuEChERS(Quick,Easy,Cheap,Effective,Rugged,Safe)净化,HP-5MS分离,气相色谱-负化学源质谱进行测定,外标法定量。在质量浓度为2.5~100μg/L范围内,氟虫腈及其3种代谢物均有良好的线性关系,所有目标物的定量限(LQD)(S/N=10)均在0.03~0.15μg/kg范围内。样品加标质量分数为0.01,0.02 mg/kg和0.05 mg/kg时,氟虫腈及其3种代谢物的平均回收率为85.6%~102.4%,相对标准偏差(RSD)为3.6%~6.1%。该方法样品前处理简单,分析时间短,回收率和精密度等均符合氟虫腈及其3种代谢物检测技术的要求,适用于牛奶中氟虫腈及其3种代谢物残留的检测。

A method was established for fipronil and its metabolites in milk with gas chromatography-negative chemical ionization mass spectrome?try(GC-NCI-MS).The targets was extracted from acetonitrile,and followed by a simple cleanup step known as dispersive solid-phase extraction QuEChERS.The derivatives of fipronil and its metabolites were separated on a HP-5MS column(30 m×0.25 mm,0.25μm)and finally detected with gas chromatography-negative chemical ionization mass spectrometry(GC-NCI-MS)in single ion monitoring(SIM)mode.The quantifica?tion analysis was performed by external standard.The method showed a good linearity in the range of 2.5~100μg/L.The limits of quantification(LQDs,S/N=10)of fipronil desulfinyl,fipronil sulfide,fipronil,fipronil sulfone were from 0.03μg/kg to 0.15μg/kg.At the spiked levels of 0.01 mg/kg,0.02 mg/kg and 0.05 mg/kg,the recoveries of fipronil and its metabolites were from 85.6%to 102.4%,and the relative standard deviations(RSDs)(n=6)were from 3.6%to 6.1%.This method is simple,rapid and characterized with acceptable sensitivity and accuracy to meet the requirements for the analysis of fipronil and its metabolites in milk.