氨氮在线监测仪示值误差测量值的不确定度评定

Evaluationonthe Indication Error Uncertaintyof On-Line Ammonia-nitrogen Monitoring Instrument

随着国家对环境预警监测能力建设投入的加大以及地表水质监测技术的日趋成熟,氨氮在线监测仪在水质自动预警监测系统中得到了更为广泛的应用。为了确保氨氮在线监测仪量值的准确性和一致性,必须采用有效的手段对其量值进行溯源。本文在给出氨氮在线监测仪示值误差数学模型的基础上,对氨氮在线监测仪进行标准不确定度分量的A类评定和B类评定,在B类评定中综合考虑了稀释定容过程引入的不确定度、稀释取液过程引入的不确定度以及氨氮标准溶液引入的不确定度。经过合成得出氨氮在线监测仪测量结果的相对扩展不确定度为2.4%,满足氨氮在线监测仪检定要求。

With the increase of investment on environmental early warning monitoring ability construction and the increasing maturity of surface water quality monitoring technology,online ammonia nitrogen monitoring instrument has been more widely used in automatic water quality early warning monitoring system. In order to ensure the accuracy and consistency of value comes from online ammonia nitrogen monitoring instrument,effective means must be adopted to its quantity traceability. On the basis of giving out mathematical model of online ammonia nitrogen monitoring instrument indication error,Type A and Type B assessment has been taken to its standard uncertainty components. Uncertainty introduced in the process of diluting constant volume,diluting liquid and standard ammonia nitrogen liquor has been taken into consideration in Type B assessment. After synthesis,relative expanded uncertainty of measurement results come from online ammonia nitrogen monitoring instrument is 2.4% that satisfies the calibration requirement of online ammonia nitrogen monitoring instrument.