高效液相色谱-高分辨质谱-同位素内标法测定乳粉中的胆碱

Determination of choline in milk powder by high performance liquid chromatography-high resolution mass spectrometry-isotope internal standard method

中文关键词:  胆碱  乳粉  同位素内标法  高分辨质谱

英文关键词:choline  milk powder  isotope internal standard method  high resolution mass spectrometry

中文摘要:

      目的 建立高效液相色谱－高分辨质谱-同位素内标法测定乳粉中胆碱的含量。方法 奶粉样品用水溶解, 加入硫酸铜溶液(70 g/L)和氢氧化钠溶液(40 g/L)沉淀蛋白, 离心后过0.45 μm粒径的微孔膜, 经ZORBAX SB-Aq C18色谱柱, 以0.1%甲酸水和乙腈为流动相进行梯度洗脱, 流速0.60 mL/min; 柱温箱温度30 ℃。质谱采用正离子模式分析, 同位素内标法定量。结果 该方法在0.5~10 μg/mL范围内线性关系良好, 相关系数为0.9998。平均加标回收率为91.4%~99.7%, 相对标准偏差为1.0%~3.2%(n=5), 检出限为0.2 mg/100 g, 定量限为0.5 mg/100 g。结论 该方法预处理简单, 分析速度快, 检测成本低, 能满足奶粉中胆碱的检测要求。

英文摘要:

      Objective To establish a method for the determination of choline in milk powder by high performance liquid chromatography-high resolution mass spectrometry-isotope internal standard method. Methods The milk powder sample was dissolved with water and added with copper sulfate solution (70 g/L) and sodium hydroxide solution (40 g/L) to precipitate the protein. After centrifugation, the supernatant was filtered through 0.45 μm membrane. The samples were separated with a ZORBAX SB-Aq C18 column at the flow rate of 0.60 mL/min by gradient elution using 0.1% formic acid water and acetonitrile. The temperature of the column oven was maintained at 30 ℃. Positive ion model of mass spectrometry was used for analysis and quantified by isotope internal standard method. Results The method showed good linear relations in the range of 0.5-10 μg/mL, with a correlation coefficient of 0.9998. The average recovery rates were 91.4%-99.7% with relative standard deviations of 1.0%-3.2% (n=5). The limit of detection was 0.2 mg/100 g and the limit of quantification was 0.5 mg/100 g. Conclusion The method has the advantages of simple pretreatment, fast analysis speed and low detection cost, and can meet the detection requirements of choline in milk powder.