金霉素和代谢物差向金霉素在肉鸡肌肉和肝脏中的残留分布

摘要

为了研究金霉素（CTC）、差向金霉素（ECTC）在肉鸡肌肉、肝脏中的残留分布情况，样品经提取液提取后过 Oasis HLB SPE 小柱净化，采用电喷雾正离子模式（ESI ＋）和多反应监测模式（MRM），用高效液相色谱－串联质谱仪检测；试验组鸡按体重以50 mg／（kg·d）剂量内服 CTC，连续5 d，每天给药1次。结果表明：该方法测定肉鸡肌肉和肝脏中 CTC 检测限和定量限分别为5．0、10．0μg／kg。ECTC 检测限和定量限分别为20．0、30．0μg／kg。CTC 和 ECTC 在肉鸡肌肉中平均回收率分别在73．0％～95．20％和81．80％～101．60％，相对标准偏差（RSD）分别在8．85％～12．18％和2．05％～9．29％；在肉鸡肝脏中平均回收率分别在67．06％～90．80％和78．64％～106．98％， RSD 分别在2．90％～8．88％和4．72％～9．48％；肉鸡肌肉和肝脏中 CTC、代谢物 ECTC 的残留量分别在给药后第1、5 d 时达到最高。肉鸡肝脏中 ECTC 的残留量约占总残留量的1／2。停药后 CTC及其代谢物 ECTC 代谢缓慢，在停药第6 d 时，仍能检测到 CTC 及其代谢物 ECTC，但其残留量均低于最高残留限量（MRLs）。从保障食品安全方面考虑，建议我国将 CTC 和 ECTC 均作为金霉素的残留标示物进行监测。%A study on chlortetracycline (CTC)and 4 -epi -chlortetracycline (ECTC)residue distribution was conducted in broiler chicken muscle and liver .The samples were extracted using (extracting solution)and purified by Oasis HLB SPE column.Electrospray positive ion mode (ESI +)and multiple reaction monitoring(MRM)were adopted.Finally,Chlortetracycline (CTC)and 4 -Epi -chlortetracycline (ECTC)in broiler chicken muscle and liver were determinated by high performance liquid chromatography coupled with tandem quadruple mass spectrometry (HPLC -MS /MS).In this method,the limits of detection (LODs)and the limits of quantitation (LOQs)of chlortetracycline were 5.0 μg/kg and 10.0 μg/kg,respectively;the LODs and LOQs of 4 -Epi -chlortetracycline were 20.0 μg/kg and 30.0 μg/kg,respectively.The average recoveries in broiler chicken muscle were 73.0% ~95.20% and 81.80% ~101.60%,with the relative standard deviation (RSD)of 8.85%~12.18% and 2.05% ~9.29%,respectively;the average recoveries in broiler chicken liver were 67.06 % ~90.80% and 78.64% ~106.98%,with the RSD of 2.90% ~8.88% and 4.72% ~9.48%,respectively.After the broiler chickens were orally administered successively chlortetracycline of 50 mg/kg of body weight one time every day for 5 d,the residues of chlortetracycline and 4 -Epi -chlortetracycline in broiler chicken muscle and liver were the highest on day 1 and day 5,respectively.The residues of 4 -epi -chlortetracycline in broiler chicken liver accounted for half of the total residues.The metabolism of CTC and its metabolite ECTC was slow and could still be detected 6 d after withdrawal of drugs under the limits of the maximum residues (MRLs).To guarantee food safety,this research suggested identification and monitoring CTC and ECTC as residue marker of CTC in China.