液相色谱-同位素稀释质谱法测定配方奶粉中的烟酰胺

Determination of Nicotinamide in Formula Milk Powder Using Liquid Chromatography-Isotope Dilution Mass Spectrometry

对复杂基体中微量化合物的准确定量是分析化学的重要目标之一。常规的方法是选择与待测物性质相似的内标物,以抵消样品处理过程的待测物损失。由于待测物的同位素标记试剂与待测物具有最为接近的物理与化学性质,所以是最理想的内标物。该文以氘代烟酰胺为内标物,采用液相色谱-同位素稀释质谱法(LC-IDMS)测定了配方奶粉中烟酰胺的含量。测定结果的相对标准偏差为0.94%。方法的准确性高、特异性高、重复性好,可实现复杂基体中维生素含量的准确测定。参加国际比对实验CCQM-P78,结果与国际实验室的结果等效一致。

It is important to determine trace compounds in complex matrices. Internal standards are often introduced to circumvent loss of analytes during the preparation to achieve accurate measurement. Isotope internal standards are better than other types of internal standards, due to its high similarity to analyte in chemical properties. By introducing isotope-labeled nicotinamide, as an internal standard, a method for determining nicotinamide in formula milk powder by liquid chromatography-isotope dilution mass spectrometry （LC-IDMS） was developed with a relative standard deviation of 0.94%. The results suggested that the developed LC-IDMS method has high accuracy, high specificity, high repeatability, and is suitable for the determination of vitamins in complex matrices. This method was used to perform international comparison for CCQM-P78, and the result was consistent with that of international laboratories.