原子吸收法测定大米粉中镉的不确定度评定

目的 采用无火焰原子吸收法对大米粉中的镉进行测定。方法 分析测量不确定的主要来源，在整个分析测定过程:称量、容量器具的体积、标准物质、直线回归方程、重复性测定和仪器示值误差等是不确定度的主要来源。结果 按照JJF 1059.1-2012《测量不确定度评定与表示》的规定进行评定，舍弃贡献小，可以忽略不计的不确定度分量，最终计算给出扩展不确定度为: K=2，U=48 μg/kg，CCd=（300.01±48.00）μg/kg。结论 该结果更加客观和接近真值，降低了检测机构的检测风险。

Evaluation of Uncertainty in Determination of Cadmium in Rice Flour by Atomic Absorption Method

Abstract:Objective To determine the cadmium in rice flour by flame atomic absorption spectrometry.Methods Analyze the main sources of measurement uncertainty.Throughout the analysis and measurement process:weighing,volume of volumetric instruments, reference materials,linear regression equations,repeatability measurements and instrumental indication errors are the main sources of uncertainty.Results According to JJF 1059.1-2012"Measurement Uncertainty Evaluation and Representation",the contribution is small, the negligible uncertainty component is discarded,and the final calculation gives the extended uncertainty as:K=2,U=48μg/kg, CCd=(300.01±48.00)μg/kg.Conclusion The result is more objective and close to the true value,which reduces the detection risk of the testing organization.