超高效液相色谱-串联质谱法测定牛奶中游离硒代蛋氨酸

Determination of free selenomethionine in cow milk by UPLC-MS/MS

目的建立超高效液相色谱-串联质谱法测定硒代蛋氨酸（SeMet）的方法，并用于测定牛奶中游离SeMet。方法在Acquity UPLC BEH C18。色谱柱（2．1mm×100mm，1．7um）上以水：乙腈：甲酸（95：5：0．1， V/V）为流动相，流速0．3mL／min，柱温40℃，分析时间2．5min，在电喷雾一正离子电离源上以多反应监测模式分析SeMet，用于定量分析的离子反应为m／z198．0—181．1。结果SeMet线性范围为0．5～100ng／mL，方法的定量下限为0．5ng／mL。SeMet批内准确度在97．6％～100．6％，批间准确度在97．7％～99．2％，批内精密度在0．53％～4．49％，批间精密度在1．03％～4．54％。结论UPLC．MS／MS法具有特异性好、灵敏度高、分析速度快和准确可靠的优点，适用于牛奶中游离SeMet的定量测定。

Objective To establish an ultra-performance liquid chromatography-tandem mass spectrometry （UPLC-MS/MS） method for the quantification of free selenomethionine （SeMet）, and be applied to the quantification of free SeMet in cow milk. Methods The analyte was separated on a BEH C18 column （2. 1 mm x 100 mm, 1.7 μm） at 40 ℃ with a mobile phase of water： acetonitrile： formic acid（95： 5： 0. 1, V/V） , a flow rate of 0. 3 mL/ min, and an analysis time of 2. 5 min. At positive electrospray ionization mode, multiple reaction monitoring of the precursor-product ion transitions of m/z 198.0-181.1 was used for the quantification. Results The linear calibration curve was obtained in a concentration range of 0.5 - 100 ng/mL with a lower limit of quantification of 0. 5 ng/mL. The value of intra- and inter-day accuracy for SeMet fell in the range of 97.6%-100. 6% and 97.7%- 99. 2% , and value of intra- and inter-day precision 0. 53%- 4. 49% and 1.03%- 4. 54%. Conclusion The method is specific, sensitive, rapid, and accurate, suitable for the quantification of free SeMet in cow milk.