同位素作内标气质联机测定动物源食品中4种β2-兴奋剂的含量

Study on determination of 4 β2-agonistic residues in foods from animal source with isotopically labelld internal standard by GC/MS

目的：建立用同位素作内标，GC／MS测定动物源食品中4种β2-兴奋剂含量的分析方法。方法：粉碎的样品中添加内标加高氯酸匀浆，用高氯酸沉淀蛋白质，正己烷脱脂，再经阳离子交换柱子（SLS）净化，再用N，O双（三甲基硅基）三氟乙酰胺-三甲基氯硅烷（BSTFA＋TMCS，99＋1）衍生化，用同位素作内标，同时测定4种p2一兴奋剂。结果：4种p2一兴奋剂对肝、肾和肉样品进行添加回收实验，平均回收率为70％～130％（n=6），变异系数为4％～16％（n=6）。结论：本方法准确性好、灵敏度高、简便、快速，为动物源食品中β2-兴奋剂的检测提供了可参考的分析方法。

Objective：To establish a practical method for the simultaneous determination of Clenbuterol, Ractopamine, Salbu-tamol ,Terbutaline residues in foods from animal source with isotopically labelld internal standard by Gas chromatograph-mass spectrometry （GC/MS）. Methods：Sample spiked with isotopically labelld internal standard was homogenized with perchloricacid, the protein was precipitated with perchloricacid, followed by defatted with hexane. Further cleanup was performed on a SLS car-tridge. The purified 4 β2-agonists and the isotope were derivatized with [N,O-bis （trimethylsilyl） trifluoroacetamide （BSTFA）-trimethylchlorosilane （TMCS） ,99＋1], internal standard and 4 β2-agonists were determined at one time. Satisfactory separation was achieved on DB-5 capillary column. Finally, 4 β2-agonists were identified by mass spectrometry. Selected ion monito-ring（SIM） method was used applied for detection. Results：The rates of recovery were between the range of 70%-130% （n=6）, with the detection limit of 1.0μg/kg and the relative standard deviations were 4% -16% （n=6）. Conclusion：The method is sensitive, accuracy, selective and reproducible so that could be used for determination of β2- agonists in animal tissue.