液相色谱-串联质谱法测定牛奶中35种四环素类、磺胺类、青霉素类、大环内酯类、氯霉素类抗生素残留

Determination of 35 antibiotic residues of tetracyclines,sulfonamides,penicillins,macrolides and amphenicols in milk by liquid chromatography-tandem mass spectrometry

建立了液相色谱.质谱测定牛奶中35种四环素类、磺胺类、青霉素类、大环内酯类、氯霉素类等5类抗生素残留的检测方法。样品经碱性乙腈.Mcllvaine缓冲液超声提取，用Eclipse XDB.C8色谱柱（150 mm×2.1 mm，3.5μm）分离，梯度洗脱，流速0.25 mL／min，进样量10μL，采用多反应监测正离子或负离子模式，可以一次性对牛奶中的目标化合物进行定性和定量测定。在优化条件下，35种化合物的检出限均低于10.0μg／kg，方法回收率为70.1％～109.9％，相对标准偏差（ RSD）为2.89％～9.99％。结果表明该方法适用于牛奶中抗生素残留的检测。采用所建立的检测方法对市售的50种不同乳品进行了检测，其中一个样品检出氯霉素含量为0.48μg／kg。检测结果表明，中国市场上销售的乳品氯霉素污染的风险仍然存在。本研究建立的液相色谱.质谱联用方法实现了牛奶中35种四环素类、磺胺类、青霉素类、大环内酯类、氯霉素类等5类抗生素残留的测定。该方法简单、快捷、经济，可实现多种抗生素残留的快速测定。

A liquid chromatography-tandem mass spectrometry （ LC-MS/MS ） method was established for the simultaneous determination of 35 antibiotic residues of tetracyclines, sulfon-amides, penicillins, macrolides and amphenicols in milk. The samples were extracted with alkaline acetonitrile and Mcllvaine buffer solution under ultrasonication. The separation of target compounds was performed on an Eclipse XDB-C8 column （ 150 mm × 2-1 mm, 3.5 μm） with gradient elution at a flow rate of 0.25 mL/min, and with an injection volume of 10 μL. The identification and quantification of the compounds were completed by liquid chromatography-tandem mass spectrometry in multiple reaction monitoring （ MRM） mode. The limits of detec-tion were all below 10.0 μg/kg. The average spiked recoveries of the method ranged from 70.1% to 109.9% with relative standard deviations （ RSDs） of 2.89%-9.99%. After validation, the method was applied to the analysis of antibiotic residues in milk products in China. Fifty samples were screened under the well defined methodology, and the results showed that chlor-amphenicol, only in one sample, was monitored with the content of 0.48μg/kg. A risk of con-tamination of milk with chloramphenicol has been determined to exist. Therefore this method is convenient, rapid, sensitive and reliable, and can be successfully applied to the simultaneous detection of the 35 antibiotic residues of tetracyclines, sulfonamides, penicillins, macrolides and amphenicols in milk.