基于纳氏比色法测定氨氮的两种不确定度评定方法的优劣比较

Comparison of Two Uncertainty Evaluation Methods for Determination of Ammonia Nitrogen Based on Nessler Colorimetry

2017年,最新的国家标准《测量不确定度评定和表示》(GB/T 27418—2017)发布。目前,测量不确定度的方法中,GUM法中一系列Bottom-Up方法的使用较为普遍。《基于质控数据环境检测测量不确定度评定指南》(CNAS-GL34)提出使用Top-Down方法进行不确定度的评定。以纳氏比色法测定水中氨氮的检测数据为基础,考察GUM法中最小线性二乘法和Top-Down法中质控图法两种方法评定检测数据的不确定度,比较分析了两种方法的优劣,初步探讨了Top-Down方法的应用前景。

In 2017,the latest national standard Measurement Uncertainty Evaluation and Representation(GB/T 27418—2017)was released.In the current method of measuring uncertainty,a series of Bottom-Up methods in GUM are more common.However,CNAS-GL34 based on the Quality Control Data Environment Measurement and Measurement Uncertainty Evaluation Guide proposes the use of Top-Down method for the evaluation of uncertainty.Based on Nash colorimetric method for the determination of ammonia nitrogen in water,the uncertainty of the test data is evaluated by the minimum linear multiplication method in GUM and the quality control chart method in Top-Down.The pros and cons of the method,and the application prospects of Top-Down method are discussed.