火焰原子吸收法测定黄豆酱中钠的不确定度评定

目的]更科学合理地表示微波消解-空气-乙炔火焰原子吸收法测定食品中钠含量的测量结果。方法]根据JJF1059．1—2012《测量不确定度评定与表示》规范要求，以火焰原子吸收法测定黄豆酱中钠为例对测量不确定度进行评定。结果]分析表明，影响测量结果的主要因素依次为试剂空白、标准物质和仪器测量时标准曲线的拟合；消解液的定容以及稀释引入的不确定度次之。用该法测得黄豆酱中钠含量为17627mg/kg，扩展不确定度为1128mg／kg（95％，k=2）。结论]该评价方法及结果对营养标签中钠的准确标示有一定的指导意义。

Evaluation on Uncertainty in Measurement of Sodium in Soybean Paste by Flame Atomic Absorption Spectrometry Method

Objective ] In order to express the measurement results tor sodium content in ibod by microwave digestion-air-acetylene flame a- tomic absorption spectrometry method more reasonably and scientifically. Method ] The uncertainty in measurement of sodium in soybean paste was evaluated according to Evaluation and Expression of Uncertainly in Measurement （ JJF 1059.1 - 2012 ）. Result] The results showed that the key factors of uncertainty were the blank of method, the standard solution and the fitting of calibration curve secondly. Constant vol- ume and dilution were less important factors of uncertainty. The concentration of sodium was 17 627 mg/kg and the expanded uncertainty was 1 128 mg/kg （95%, k = 2）. Conclusion] The evaluation methods and results were important to label sodium content of nutrition label accu- racy.