液相色谱-串联质谱法测定牛奶中米尔贝霉素类药物残留

Determination of milbemycins residues in milk by liquid chromatography-tandem mass spectrometry

目的应用液相色谱-串联质谱技术,建立牛奶中奈马克丁、米尔贝霉素A3、米尔贝霉素A4、米尔贝霉素D和莫西丁克等5种米尔贝霉素类药物残留检测方法。方法用乙腈提取牛奶样品中的目标物,C18固相萃取柱净化,Agilent Poroshell 120 EC-C18色谱柱分离,以0.1%甲酸水溶液和甲醇为流动相梯度洗脱,然后用液相色谱-串联质谱仪在正离子多反应监测(MRM)模式下测定。结果 5种化合物在10~100μg/kg范围内线性良好,相关系数大于0.99,平均回收率为77.5%~100%,相对标准偏差小于11.6%。结论 本方法灵敏度高,重现性好,适用于牛奶中米尔贝霉素类药物残留检测。

Objective To develop a method to determine residues of 5 milbemycins-moxidectin, milbe-mycin A3, milbemycin A4, milbemycin D and nemadectin in milk by liquid chromatography-tandem mass spectrometry (LC-MS/MS).MethodsThe residues of milbemycins in milk samples were extracted by aceto-nitrile and purified by a C18 SPE column. After being separated by an Agilent Poroshell 120 EC-C18 chromato-graphic column with gradient elution using 0.1% formic acid aqueous and methanol, the extracts were deter-mined by LC-MS/MS under the positive ion mode with multi-reaction monitoring (MRM).ResultsThe cali-bration curves of 5 milbemycins were linear in the range of 10~100 μg/kg, with the correlation coefficients (R) >0.99. Average recoveries were 77.5%~100% with relative standard deviations less than 11.6%. Conclu-sionThe method is suitable for the determination of milbemycins residues in milk due to its high sensitivity and good reproducibility.