液相色谱-质谱/质谱法测定牛奶和奶粉中地塞米松残留量

Determination of Dexamethasone Residues in Milk and Milk Powder Using LC-MS-MS

本文建立了一种测定牛奶和奶粉中地塞米松残留量的液相色谱-质谱/质谱方法。样品用乙腈提取,C18固相萃取柱净化,液相色谱-质谱/质谱仪测定,采用基质匹配外标曲线法定量。在2.0-400 ng/mL浓度范围内呈良好线性。本方法的测定低限:牛奶为0.2μg/kg,奶粉为1.0μg/kg。牛奶样品在添加浓度0.2-10μg/kg范围内,回收率为70.0%-110.0%;奶粉样品在添加浓度1.0-10μg/kg范围内,回收率范围为65.0%-100.0%。相对标准偏差在8.65%-12.8%之间。

A LC - MS - MS method is developed to determine dexamethasone residues in milk and milk powder. The milk and milk powder sample were extracted by acetonitrile, the extractions were cleaned up with C 18 column. Determination is made by LC - MS/MS using the external standard method. The limit of detection（LOD） ： milk is 0.2 I^g/kg; milk powder, 1.0 p,g/kg. The good linear relationships were obtained in the range of 2.0 - 400 ng/mL using matrix standard solution. The. spiked levels of milk sample were 0.2 - 10 p^g/kg, the recoveries, in the range of 70.0% - 110.0% ; The spiked levels of milk powder sample were 1.0 - 10 μg/kg, the recoveries, in the range of 65.0% - 100.0%. The RSDs were in the range of 8.65% - 12.8%.