Abstract: A method for the determination of 21 veterinary drugs in cow and goat milk and milk powder was established by the QuEChERS (quick, easy, cheap, effective, rugged, safe) sample pretreatment method combined with ultra performance liquid chromatography-quadrupole/orbitrap mass spectrometry (UPLC-Q/Orbitrap MS). Chromatographic conditions, mass spectrometric parameters and pretreatment conditions were optimized. Samples were extracted with acetonitrile in the presence of anhydrous sodium sulfate, purified using a mixture of primary secondary amine (PSA) and C18, separated on an Accucore RP-MS column (100 mm × 2.1 mm, 2.7 μm), and detected by UPLC-Q/Orbitrap MS. Good linearity was observed for all the analytes in the investigated concentration ranges with correlation coefficients (r2) of greater than 0.99. The limit of quantification (LOQ) of the proposed method was 0.5 μg/kg. The average recoveries at spiked concentration levels of 0.5, 2.0 and 10.0 μg/kg were 67.2%–110.2% with relative standard deviations (RSDs) of 3.6%–17.4% (n = 6). The method is simple and sensitive, and suitable for simultaneous detection of the 21 veterinary drugs in cow and goat milk and milk powder.

Key words: QuEChERS; electrostatic field orbitrap mass spectrometry; antiparasitics; antiphlogistics; glucocorticoids

摘要： 采用QuEChERS方法处理样品，使用超高效液相色谱-四极杆/静电场轨道阱质谱（ultra performance liquid chromatography-quadrupole/orbitrap mass spectrometry，UPLC-Q/Orbitrap MS）进行测定，建立牛羊乳及其乳粉中21 种兽药的分析方法。通过优化色谱条件、质谱参数和前处理条件，确定最佳测试方法。样品经乙腈盐析超声提取后，采用N-丙基乙二胺和C18净化，经Accucore RP-MS色谱柱（100 mm×2.1 mm，2.7 μm）分离，UPLC-Q/Orbitrap MS测定。结果表明：21 种兽药在各自线性范围内具有良好的线性关系，相关系数（r2）均大于0.99；方法定量限为0.5 μg/kg；在0.5、2.0、10.0 μg/kg加标水平下的平均回收率为67.2%～110.2%，相对标准偏差为3.6%～17.4%（n=6）。该方法简便、灵敏，适用于牛羊乳及其乳粉中21 种兽药的同步检测。

关键词: QuEChERS；静电场轨道阱质谱；抗虫药；消炎药；糖皮质激素