原子吸收光谱法测定土壤中重金属Pb、Cu含量的测量结果不确定度评定

Uncertainty Evaluation of the Heavy Metal in Soil such as Lead and Copper by Atomic Absorption Spectrophotometer

文中对火焰原子吸收法测定土壤中Pb、Cu含量的不确定度来源进行了详细分析,包括:标准溶液引入的不确定度、样品称量引入的不确定度、容量瓶和移液管体积引入的不确定度、温度引入的不确定度、校准曲线引入的不确定度和测量的重复性引入的不确定度,并按数学模型计算出各不确定度分量、合成标准不确定度和扩展不确定度。结果表明:标准物质的稀释过程、曲线的校准和样品重复性试验为不确定度的主要来源。

The sources for the uncertainty were analyzed in detail for the determination of lead and copper in soil by atomic absorption spectrometric method. The results showed the total uncertainty was mainly introduced by the following factors： standard solution, sample mass, volumetric flask and burette, temperature, calibration curve and measurement repeatability. The components of uncertainty, the combined uncertainty and expanded uncertainty were calculated by mathematical mode. The results showed that the dilution of standard solutions, calibration curve and measurement repeatability were the main sources of uncertainties.