液相色谱-三重四极杆/线性离子阱复合质谱技术检测牛奶中莫昔克丁残留

Determination of Moxidectin Residue in Milk by LC-QTRAP

建立了牛奶中莫昔克丁残留检测的液相色谱-三重四极杆/线性离子阱复合质谱技术(LC-QTRAP)。样品用乙腈提取后,用C18固相萃取柱净化,上机测试。液相色谱条件:色谱柱为BEH C18(50 mm×2.1 mm,1.7μm),流动相为0.1%甲酸水溶液+0.1%甲酸乙腈溶液,梯度洗脱,流速为0.4 mL/min,柱温为30℃,进样量为5μL。质谱条件:电喷雾正离子源(ESI^+),采用多反应监测-信息依赖扫描-增强子离子扫描(MRM-IDA-EPI)方式采集。结果表明:在牛奶中,莫昔克丁在1~80 ng/mL基质匹配标准溶液浓度范围内均呈现良好的线性关系,相关系数(R^2)大于0.990,定量限为2μg/kg。牛奶中莫昔克丁在2、40和80μg/kg三个添加浓度平均回收率都在60%~120%之间,批内、批间RSD均小于15%。该方法简便快捷、定性准确、灵敏度高,回收率和精密度满足残留检测要求。

A LC-QTRAP method was established for the determination of Moxidectin residue in milk. The samples were extracted by acetonitrile, then purified with C18 SPE. LC conditions were as follows: the chromatography column is BEH C18 column of 50 mm×2.1 mm, 1.7 μm;mobile phase is acetonitrile(0.1% formic acid) and water(0.1% formic acid);flow rate is 0.4 mL/min;column temperature is 30 ℃;injection volume is 5 μL. Mass spectrometry conditions were ESI^+ and Multi-reaction Monitoring-Information Dependent Acquisition-Enhanced Product Ion(MRM-IDA-EPI) mode. The calibration curve of Moxidectin were good linear from 1 to 80 ng/mL in milk with the correlation coefficient R^2 over 0.990. The limit of quantification was 2 μg/kg. The average recoveries of Moxidectin from spiked milk at three concentrations of 2, 40 and 80 μg/kg were between 60% and 120%, intra-batch and inter-batch RSD were both less than 15%.