微波水解/超高效液相色谱-串联质谱法快速 测定乳粉中的胆碱和左旋肉碱

Rapid determination of choline and L-carnitine in milk powder by ultra-high performance liquid chromatography tandem mass spectrometry using microwave digestion for sample preparation

中文关键词:  微波水解  超高效液相色谱-串联质谱法  乳粉  胆碱  左旋肉碱

英文关键词:microwave digestion  ultra-high performance liquid chromatography-tandem mass spectrometry  milk powder  choline  L-carnitine

中文摘要:

      目的 利用微波消解技术对乳粉样品进行水解, 释放结合态的胆碱和左旋肉碱, 优化乳粉中胆碱和左旋肉碱的微波水解快速提取方法以及超高效液相色谱-串联质谱(UPLC-MS/MS)检测的条件参数。方法 乳粉样品用温水复溶后, 取适量样品加入1.5 mol/L的盐酸溶液, 100 ℃微波消解10 min后调节pH至中性, 稀释后以HSS T3 UPLC色谱柱和0.1%甲酸水溶液(V:V)-乙腈进行梯度洗脱分离, 以串联质谱的多反应监测模式检测, 内标法定量。结果 方法线性范围1.00~500 μg/L, 相关系数(r2)0.998以上, 胆碱和左旋肉碱定量限分别为0.24 mg/100 g和0.63 mg/100 g, 3个添加水平的回收率分别为93.6%~102%, 相对标准偏差为1.9%~4.0%。日间精密度分别为2.7%和4.1%。结论 本方法分析速度快、灵敏度高、重复性好, 与现有技术对比, 该方法通过微波技术辅助水解, 缩短了样品处理的时间, 适用于乳粉中的胆碱和左旋肉碱的检测。

英文摘要:

      Objective To establish a simple and rapid method for determination of choline and L-carnitine in milk powder by ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) using microwave digestion for sample preparation. Method The sample was extracted by microwave digestion with 1.5 mol/L HCl solution at 100 ℃ for 10 min, and then diluted by water. The sample was separated on an HSS T3 UPLC column with acetonitrile and 0.1% formic acid solution as mobile phase under gradient elution mode, then detected by tandem mass spectrometry under ESI at positive and multiple reaction monitoring (MRM) mode. Stable isotope was used as an internal standard for quantification. Result Choline and L-carnitine showed good linear relationships in the range of 1.00~500 μg/L (r2>0.998), and the limits of quantitation (LOQ) of choline and L-carnitine were 0.24 mg/100 g and 0.63 mg/100 g respectively. The fine recoveries (93.6%~102%), the relative standard deviations (1.9%~4.0%) and RSD of inter-day (2.7% and 4.1%) of this method were also obtained. Conclusion Compared with the standard method, the proposed method is rapid, sensitive, and accurate. It shortens the sample preparation time by microwave digestion, and is suitable for the determination of choline and L-carnitine in milk powder.