液相色谱-串联质谱法测定鸡蛋中氟虫腈及其3种代谢物的含量

LC-MS/MS Determination of Fipronil and Its 3 Metabolites in Eggs

采用液相色谱-串联质谱法测定鸡蛋中氟虫腈及其3种代谢物的含量。鸡蛋样品经乙腈提取,离心后上清液用氮气吹至近干,残渣用水溶解后,经HLB固相萃取柱净化。以Shim-pack XR-ODS C_(18)色谱柱为分离柱,以不同体积比的4mmol·L^(-1)乙酸铵溶液和甲醇的混合液为流动相进行梯度洗脱,采用电喷雾负离子源和多反应监测模式检测。氟虫腈及其3种代谢物的质量分数均在1~50μg·kg^(-1)内与其对应的峰面积呈线性关系,检出限(3S/N)均为0.3μg·kg^(-1)。在1,5,20μg·kg^(-1)等3个浓度水平进行加标回收试验,回收率为89.9%~96.1%,测定值的相对标准偏差(n=6)为1.6%~3.3%。

LC-MS/MS was applied to the determination of fipronil and its 3 metabolites in eggs.The egg sample was extracted with acetonitrile.After centrifugation,the supernatant was evaporated to near dryness by N2-blowing.The residue was taken up with water and then purified with HLB solid phase extraction column.Shim-pack XR-ODS C18 chromatographic column was used as stationary phase,and the mixture of 4 mmol·L-1 ammonium acetate solution and methanol mixed in different ratios was used as mobile phase in gradient elution.ESI-and multireactions monitor mode were adopted in MS/MS.Linear relationships between values of peak area and mass fraction of fipronil and its 3 metabolites were kept in the same range of 1-50μg·kg-1,with same detection limit（3 S/N）of 0.3μg·kg-1.Tests for recovery were made by standard addition method at the concentration levels of 1,5,20μg·kg-1,giving values of recovery and RSD′s（n=6）in the ranges of 89.9%-96.1% and 1.6%-3.3%respectively.