石墨炉原子吸收分光光度法测定土壤中铍的不确定度评定研究

Uncertainty in Determining Beryllium Content in Soil by Graphite Furnace Atomic Absorption Spectrophotometry

根据石墨炉原子吸收分光光度法(GFAAS)测定土壤中铍的过程,建立相应的数学模型并对模型中各个参数进行了不确定度来源分析。依据测量不确定度的评定理论,对样品称量、定容体积、标准溶液的配制、曲线拟合、仪器测量重复性、干物质含量等影响不确定度的分量进行计算,给出了合成标准不确定度和扩展不确定度,结果表明,测定结果的不确定性主要来源于标准拟合引入的不确定度,其次为仪器重复测定引入的不确定度,该评定方法为石墨炉原子吸收分光光度法测定土壤中重金属元素的不确定度评定提供参考依据。

According to the process of determining Beryllium in soil using graphite furnace atomic absorption spectrometry ( GFAAS) , a mathematic model was established and the uncertainty source of each parameter was analyzed. According to the the-ory of measurement uncertainty evaluation, the uncertainty components such as sample weighing, the volume size, preparation of standard solutions, curve fitting, measurement repeatability, dry matter content and other factors were calculated, and then, the combined standard uncertainty and expanded uncertainty were obtained. The results showed that the uncertainties came mainly from the uncertainty of curve fitting;secondly from the uncertainty of repeatability. The current work provides reference for uncer-tainty evaluation of measurement of heavy metals in soil using graphite furnace atomic absorption spectrophotometry.