火焰原子吸收光谱法测定牛乳中钠含量的不确定度评定

Evaluation of Uncertainty in Determination of Sodium in Milk by Flame Atomic Absorption Spectrometry

目的:依据《食品安全国家标准食品中钾、钠的测定》(GB 5009.91—2017),利用火焰原子吸收光谱法测定牛乳中钠的含量并对其进行不确定度的评定。方法:通过对数学模型中各影响因素的不确定度量化分析,最终得到合成相对标准不确定度和扩展不确定度。结果:牛乳中钠含量为40.71 mg/100 g,扩展不确定度为0.76 mg/100 g(k=2)。结论:不确定度主要来源是标曲工作液的配制和标准曲线的拟合两方面,评定不确定度的结果可以给火焰原子吸收光谱法测定牛乳中钠含量的准确性提供参考。

Objective:According to GB 5009.91—2017,the content of sodium in milk was determined by flame atomic absorption spectrometry and its uncertainty was evaluated.Method:The synthetic relative standard uncertainty and extended uncertainty were obtained by quantitative analysis of the uncertainty of each influencing factor in the mathematical model.Result:The sodium content in milk was 40.71 mg/100 g,and the extended uncertainty was 0.76 mg/100 g(k=2).Conclusion:The main sources of uncertainty are the preparation of standard curve and the fitting of standard curve.The results of uncertainty evaluation can provide reference for the accuracy of determination of sodium content in milk by flame atomic absorption spectrometry.