Helm Irja, Jalukse Lauri, Vilbaste Martin, Leito Ivo
Institute of Chemistry, University of Tartu, Jakobi 2, 51014 Tartu, Estonia.
Anal Chim Acta. 2009 Aug 26;648(2):167-73. doi: 10.1016/j.aca.2009.06.067. Epub 2009 Jul 4.
In this report a gravimetric micro-Winkler titration method for determination of dissolved oxygen concentration in water is presented. Mathematical model of the method taking into account all influence factors is derived and an uncertainty analysis is carried out to determine the uncertainty contributions of all influence factors. The method is highly accurate: the relative expanded uncertainties (k=2) are around 1% in the case of small (9-10 g) water samples. The uncertainty analysis carried out in characterizing the uncertainty of the method is the most comprehensive published for a micro-Winkler method, resulting in experimentally obtained estimates for all uncertainty sources of practical significance (around 20 uncertainty sources altogether).
本报告介绍了一种用于测定水中溶解氧浓度的重量微温克勒滴定法。推导了考虑所有影响因素的该方法的数学模型，并进行了不确定度分析，以确定所有影响因素的不确定度贡献。该方法具有很高的准确性：对于小体积（9 - 10克）水样，相对扩展不确定度（k = 2）约为1%。在表征该方法不确定度时所进行的不确定度分析是已发表的关于微温克勒法最全面的分析，得出了所有具有实际意义的不确定度来源的实验估计值（总共约20个不确定度来源）。
