茶叶中锌含量的测量不确定度评定

Evaluation of the Uncertainty in the Determination of Zinc in Tea

通过对火焰原子吸收光谱法测定茶叶中锌含量的整个测定过程进行研究,系统分析该法测量结果的不确定度来源,并对不确定度各个分量进行评估和合成。结果显示,测量用样品不确定度分量是影响锌含量测定不确定度的主要原因,当锌测定结果为15.76mg/kg时,扩展不确定度为2.68mg/kg。该样品锌测定结果为C=(15.76±2.68)mg/kg,k=2,P=95%。

The whole procedure of flame atomic absorption spectrometry determination of zinc in tea was traced to systematically analyze the source of determination uncertainty and subsequently assess and synthesize each component of uncertainty.Results show that the variation of zinc content in the tea solution was a major source of determination uncertainty.When the content of zinc was determined to be 15.76 mg/kg,the uncertainty was consequently extended to 2.68 mg/kg.An expression of uncertainty was proposed as C=（15.76±2.68） mg/kg,k=2,P=95 %.