火焰原子吸收光谱法测定白酒中铅的不确定度分析

Analysis Uncertainty in Determination of Lead in White Spirit by Flame Atomic Absorption Spectrometry

目的建立火焰原子吸收光谱法的不确定度评定方式。方法依据《计量认证/审查认可(验收)评审准则宣贯指南》,建立数学模型,合成不确定度。结果对白酒中铅测定由标准物质引入的相对不确定度分项为3.5×10-3,标准溶液配制引入的相对不确定度分项为1.1×10-2,样品吸取引起的相对标准不确定度分项为2.1×10-3,样品溶液制备引起的相对标准不确定度分项为1.0×10-3,测量重复性引入的相对不确定度分项为2.17×10-2,分析仪器引入的相对不确定度分项为1.5×10-4,合成相对不确定度为4.0×10-2,扩展不确定度为0.08。结论根据不确定度评定结果可以判定测量重复性引入不确定度贡献最大。

[Objective]To establish the method for uncertainty evaluation of flame atomic absorption spectrometry.[Methods]According to ＂The Measurement Authentication/Publicizing Guidelines for Assessment Criteria of Acceptance＂,the mathematical model was established for synthesis uncertainty.[Results] Relative uncertainty subitem from reference materials for lead determination in white spirit was 3.5×10-3,that from standard solution preparation,sample absorption,preparation of sample solution,measurement repeatability,analytical instruments was 1.1×10-2,2.1×10-3,1.0×10-3,2.17×10-2,1.5×10-4,respectively.The relative combined uncertainty and expanded uncertainty was 4.0×10-2and 0.08 respectively.[Conclusion]The assessment results can determine that measurement repeatability contribute most to uncertainty.