石墨炉原子吸收法测定土壤中镉的测量不确定度评定

石墨炉原子吸收法测定土壤中镉的不确定度主要来源于称量样品、定容样品消解液、测定样品消解液中镉的质量浓度及测定土壤水分引入的不确定度。对各不确定度分量进行了计算,求得合成标准不确定度和扩展不确定度分别为0.0026、0.005mg/kg。镉测量不确定度的主要来源是测定样品消解液中镉质量浓度引入的不确定度。

EVALUATION OF THE UNCERTAINTY OF MEASUREMENT OF CADMIUM IN SOIL BY GFAAS

Based on the systematic analysis of the uncertainty of measurement of Cd in soil determined with graphite furnace atomic absorption spectrometry, the sources of the uncertainty were analyzed. The uncertainty sources were comprised of sample weighing, constant volume, the determination of Cd concentration in soil solution and moisture in soil sample. The combined standard uncertainty and expanded uncertainty were 0.002 6, 0.005 mg/kg respectively. The evaluation indicated that the major source of uncertainty was the determination of Cd concentration in soil solution.