超高效液相色谱-四极杆-飞行时间质谱法快速筛查牛奶中的农药和兽药残留

利用超高效液相色谱-四极杆-飞行时间质谱(UPLC-Q-TOF-MS)技术建立了牛奶中42种农药和兽药残留的快速检测方法。目标药物包括常用的13种农药和29种兽药,采用QuEChERS（Quick, Easy, Cheap, Effective, Rugged, and Safe）方法进行样品前处理。牛奶样品经含1%甲酸的乙腈溶液提取,同时加入无水硫酸钠和氯化钾盐析,提取液经C18填料净化后直接测定。目标药物经ACQUITY UPLCTMBEH C18柱分离,以乙腈和0.1%甲酸水溶液为流动相进行梯度洗脱,采用正离子全信息串联质谱扫描模式(MSE)进行检测。结果表明,牛奶中42种农药和兽药的定量限(LOQ, S/N=10)为1～100 μg/kg; 3个加标水平的平均回收率为68.2%～129.1%,相对标准偏差为2.8%～30.8%。该方法快速简便、灵敏度较高,可用于牛奶中42种农兽药的快速筛查。

Determination of residues of pesticides and veterinary drugs in milk by ultra performance liquid chromatography coupled with quadrupole-time of flight mass spectrometry

An analytical method was established for the simultaneous determination of 42 pesticides and veterinary drugs in milk by ultra performance liquid chromatography coupled with quadrupole-time of flight mass spectrometry (UPLC-Q-TOF-MS). The target compounds are the commonly used drugs including 13 pesticides and 29 veterinary drugs. The QuEChERS （Quick, Easy, Cheap, Effective, Rugged, and Safe） method was used for sample preparation. The analytes in milk samples were extracted with acetonitrile containing 1.0% (v/v) formic acid, and were salted out by adding anhydrous sodium sulfate and potassium chloride. After that, the extract solution was purified by dispersive solid phase extraction with C18 sorbent. In the chromatographic analysis of 42 target compounds were separated on an ACQUITY UPLCTMBEH C18 column with the gradient elution using the mobile phases of acetonitrile and water containing 0.1% formic acid. MSE (where E represents collision energy)acquisition under positive ion mode was performed to obtain accurate relative molecular masses and fragment ions. As a result, the limits of quantification (LOQ, S/N=10) of the target compounds were from 1 μg/kg to 100 μg/kg in milk. The average recoveries of the 42 analytes spiked at three concentration levels were ranged from 68.2% to 129.1% with the relative standard deviations of 2.8%-30.8%. This method can be applied to the analysis of the 42 pesticides and veterinary drugs in milk due to its fastness, simplicity and relatively high sensitivity.