液相色谱-质谱联用法测定乳品中维生素D3质量浓度

Determination of Vitamin D3 in milk products by liquid chromatography tandem mass spectrometry

建立了液相色谱-质谱联用法测定乳品中维生素D3质量浓度。试样经乙醇-50％氢氧化钾溶液皂化后，正己烷萃取，饱和氯化钠溶液净化，YMCC18色谱柱（50mm×2．1mm，3μm），甲醇-5mmoL／L甲酸铵溶液作为流动相，梯度洗脱进行液相分离，采用电喷雾正离子方式，多反应选择离子监测，内标法峰面积定量。乳品中维生素D3质量浓度在0-50μg/L范围内线性良好，相关系数r均大于0．99，样品在20，100和200μg／kg三个质量浓度水平的添加平均回收率为83．9％～93．0％之间，变异系数为1．10％～4．90％（n=6），方法的定量限为20μg／kg。方法简便、准确，适用于婴幼儿食品和乳品中维生素D3的检测。

To develop a liquid chromatography tandem mass spectrometry （LC-MS/MS）method for the determination of vitamin D3 in milk products .The sample was saponified with ethanol - 50 % potassium hydroxide, followed by extraction with hexane and cleaned up by saturated sodium chloride solution. The chromatographic separation was performed on the YMC C18 column （50 minx 2.1 mm, 3 μm）,using methanol-5 mmol/L ammonium formate solution as the mobile phase by gradient elution . The method apphed positive electrospray ionization and multiple reaction monitoring mode and quantified with peak area with internal standard method .A good linearity was ob- tained for 0-50 μg/L with a correlation coefficient above 0.99.The average recoveries from three different were with the range of 83.9% to 93.0% at spiked levels of 20,100,200 μg/kg ,and the relative standard deviations were between 1.10% to 4.90%（n=6）.The hmit of quantification was 20 μg/kg. This method is simple, accurate and suitable for determination of vitamin D3 in milk products.