原子荧光光度法测定海水中硒的不确定度评定研究

通过实例对原子荧光法测定海水中硒的不确定度进行评定。根据(JJF 1059-1999)《测量不确定度评定与表示》中对测量和评定不确定度的要求评估了不确定度。测量不确定度的产生包括标准溶液的逐级稀释、工作曲线的非线性和原子荧光光度计的测量性能及取样体积。结果表明取样体积是导致该方法不确定度产生的主要影响因素,在测定时应加强这方面的控制,从而提高测量结果的准确性。当海水中硒的含量为1.99μg/L时,硒含量的扩展不确定度为0.40μg/L,置信水平为95%。

Uncertainty in Determining Selenium in Seawater by Atomic Fluorescence Spectrometry

Atomic Fluorescence Spectrometry was taken to determine selenium in seawater. The uncertainty level was deter- mined according to JJF1059 - 1999 ＂Evaluation and Expression of Uncertainty in Measurement＂. The uncertainty were caused by gradual diluted standard stock solution, standard curve and measurement performance of atomic fluorescence spectrometry, sample volume. Results show that the sampling volume is the main influencing factors of uncertainty in the method. Attentions should be paid to strengthen the control so as to improve the accuracy of measurement results. When the content of selenium in seawater is 1.99 μg/L and the expanded selenium detection uncertainty is 0. 40 μg/L, the certainty degree is 95%.