The uncertainty assessment aspect of AAS determination for zinc content in milk powder was established, and the observed valve was dispersed reasonably. The factors caused uncertainty were analyzed and e-valuated with determination of zinc in milk powder by AAS method according to JJF1059-1999. The combined standard uncertainty and calculated expanded uncertainty were calculated and resulted by uncertainty. The relative expansion uncertainty of the method is 5.4%, sample measurement expansion uncertainty is 0.42mg/100g, measurement result is (3.90±0.42)mg/100g. The assessment aspect is also workable for uncertainty assessment of AAS determination for other metal ions such as zinc, iron content in edibles.%建立了原子吸收光谱法测量奶粉中锌含量的不确定度评定方案,合理地赋予被测量值的分散性.本文根据JJF1059-1999技术规范要求,以AAS法测定婴儿奶粉中锌含量为例,全面分析了测量过程中引起不确定度的各种因素,并评估各不确定度的分量,计算得到合成标准不确定度和计算扩展不确定度,以不确定度的形式报告测量结果.本例的相对标准不确定度为5.4％,扩展不确定度为0.42mg/100g,测量结果为(3.90±0.42)mg/100g.评定方案适用于AAS法测定食品中锌、铁等金属离子含量的不确定度评估.
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