液相色谱-质谱法测定饲料中阿维菌素类药物

Determination of avermectins in feeds by liquid chromatography-mass spectrometry

建立了饲料中阿维菌素类药物（阿维菌素、多拉菌素、埃普菌素和伊维菌素）液相色谱．质谱（LC-MS）检测法。用乙腈提取样品中的药物，加水稀释，加三乙胺调节pH，经C18固相萃取柱净化，LC-MS法测定。结果表明，方法平均回收率为91．3％～99．8％，RSD为2．9％～15％（n=4），配合饲料、浓缩饲料和预混合饲料中的检出限均为10μg／kg；定量限均为20μg／kg。方法可用于饲料样品中阿维菌素类药物残留量的确证检测。

An analytical method of avermectins （avermectin, dormectin, eprinomectin and ivermectin） was established by LC-MS. 4 kinds of avermectins were simply extracted with acetonitrile from feeds. Then, the extraction was diluted with water and pH was adjusted with triethylamine. Target compounds were selectively concentrated by C18 SPE cartridge. They were determined by LC-MS. The average recoveries for 4 avermectins were ranged from 91.3% to 99.8%. The coefficients of variation were in the range of 2.9% - 15% （ n = 4）. The limits of detections were 10 μg/kg and the quantitative limits were 20 μg/kg for complete feeds, concentrated feeds and premixed feeds. The method can be used for confirmation of the detection of avermectin residues in feeds.