原子吸收法测定海水中铁含量的不确定度评定

为了保证海水中铁元素含量的检测质量,更好地深入了解铁在整个海水体系的生物地球化学中扮演的角色,需科学地评定检测结果的分散性。文章依据《测量不确定度的评定与表示》(JJF1059-1999)的理论,以浙江近海海水为例,评定原子吸收法测定海水中铁含量的不确定度。测得浙江近海样品中铁的浓度为5.2μg/L,扩展不确定度U=0.8μg/L(k=2)。通过对各不确定度分量进行评定发现,利用该方法测定海水中铁含量时,对其合成标准不确定度的主要贡献来自于样品制备过程,尤其是萃取过程。

Evaluation of the Uncertainty for Measurement of Iron in Seawater by Atomic Absorption Spectrometry

In order to ensure the detection quality of the iron content in seawater and better understand the role of iron in the marine biogeochemical process of the whole marine system,it is necessary to scientifically evaluate the dispersity of the detection results.In this paper,on the basis of the theory of "Measurement Uncertainty Evaluation and Representation" (JJF1059-1999),offshore water in Zhejiang is taken as an example to determine the uncertainty of the iron content in seawater by atomic absorption spectrometry.The results show that the concentration of iron in the samples from Zhejiang coastal is 5.2 μ g/L with its expanded uncertainty as U=0.8 μ g/L (k=2).By evaluation of the components of the uncertainty,it is found out that the main contribution to the standard uncertainty of the measurement of iron in seawater is the process of sample preparation,especially the extraction process.