Evaluation of Uncertainty of Chemical Oxygen Demand Measure in Drinking Water
- VernacularTitle:饮用水中耗氧量测量不确定度的评定
- Author:
Chonglin YAO
;
Wei TONG
;
Dan DU
- Publication Type:Journal Article
- Keywords:
Water;
Chemical oxygen demand;
Uncertainty
- From:
Journal of Environment and Health
1993;0(03):-
- CountryChina
- Language:Chinese
-
Abstract:
Objective To estimate the marginal value of the chemical oxygen demand (COD) in drinking water by evaluation of uncertainty. Methods According to Evaluation and Expression of Uncertainty in Measurement (JJF1059-1999), analysis of measure uncertainty of the chemical oxygen demand determined by acidic potassium permanganate titrate prescribed in Sanitary Standards for Drinking Water (2001) was conducted. Results The type A relative standard uncertainty was 0.584%, type B was 0.781%, in which the sub-item uncertainty led by using 25 ml burette was 0.708%, the water sample volume was 0.056%, the adjusted potassium permanganate standard solution was 0.325%; the relative combined standard uncertainty was 0.975%, the expanded uncertainty was 1.95%. Conclusion According to the result of the uncertainty (3.08?0.06) mg/L, COD in the polluted sample exceeds the limit, the use of 25 ml burette produced the most contribution to the uncertainty.
