电位测定法测海水氧化还原电位的不确定度评定

Uncertainty Evaluation of the Oxidation-Reduction Potentials of Sea Water Using the Potentiometric Method

采用电位测定法对实际海水的氧化还原电位进行测定,分析了影响测量不确定度的主要来源,对曲线拟合、测定过程的标准溶液的使用、仪器使用和测量重复性等影响不确定度的分量进行分析,按JJF1059—1999《测量不确定度评定与表示》的规定进行合成,最终给出扩展不确定度。结果表明,实际海水电位值的合成标准不确定度为14.18 mV,扩展不确定度为28.4 mV(近似95%置信概率)。这样结果的表达更加客观和真实,更具有参考意义。

The oxidation-reduction potentials of sea water were measured by potentiometric method. The major source of measurement uncertainty in three aspects of curve fitting and the determination of the use of standard solution process, instrumentation and measurement of repeatability were analyzed. By the requirement of JJF1059-1999 〈〈Evaluation and Expression of Uncertainty in Measurement） for synthesis, the expanded uncertainty was given ultimately. The results show that the combined standard uncertainty of potential value of sea water is 14.18 mV, and expanded uncertainty is 28.4 mV （approximate 95% confidence level）. This expression results are more objective, real and more referenced.