火焰原子吸收光度法测定水中铜的不确定度评定

Evaluation of Uncertainty in Determination of Copper in Water by Flame Atomic Absorption Spectrometry

以火焰原子吸收光度法测定水中的铜为例,阐明铜测量不确定度分量来自溶液移取过程、标准系列溶液的配置、标准曲线拟合、样品重复测定和仪器引入。对各分量不确定度进行评定,结果表明:配制铜标准曲线的相对不确定度U_(rel1)=0.025 3和仪器引入的相对不确定度U_(rel3)=0.019 5是测定铜的主要不确定度来源;重复测定铜质控样(200929)10次,C_均=0.646 mg/L,合成标准不确度U_c=0.021 mg/L,扩展不确定度U_(95)=0.047 mg/L(k=2),铜测量结果为:0.646±0.047mg/L。

The The determination of copper in water by flame atomic absorption spectrometry as an example shows that the uncertainty of copper measurement comes from the solution migration process, the configuration of standard series solution, the fitting of standard curve, the repeated determination of samples and the introduction of instruments. For each component of uncertainty was evaluated. The results showed that the preparation of copper standard curve and the relative uncertainty of U（rel1）=0.025 3 and instrument into the relative uncertainty of U（rel3）=0.019 5 determination of copper is the main sources of the uncertainty of determination of copper; repetitive control sample（200929） 10 times, C（AVG）=0.646 mg/L, the combined standard uncertainty Uc=0.021 mg/L U（95）=0.047 mg/L, the expanded uncertainty（k=2）, copper measurement results are as follows： 0.646＋0.047 mg/L.