含乳饮料中蛋白质含量测定结果的不确定度评定

对凯氏定氮法测定含乳饮料中蛋白质含量进行测量不确定度来源分析,结果的适用性给出合理的建议。依据JJF 1059.1—2012,分析测量过程中影响不确定度的因素,进行评估合成。结果表明,空白测定和测量重复性是主要的不确度来源,含乳饮料中蛋白质结果为1.53 g/100 g时,扩展不确定度为0.13 g/100 g,因此蛋白质含量测定结果可表示为(1.53±0.13)g/100 g(k=2)。

Uncertainty Evaluation of Measurement Result of Protein Content in Milk Beverage

The Kjeldahl method was used to determine the protein content of milk-containing beverages to analyze the sources of measurement uncertainty,and reasonable suggestions were given for the applicability of the results.According to JJF 1059.1—2012,analyze the factors that affect the uncertainty in the measurement process,and conduct evaluation and synthesis.The results show that blank determination and measurement repeatability are the main sources of uncertainty.When the protein result of milk-containing beverage is 1.53 g/100 g,the expanded uncertainty is 0.13 g/100 g,so the protein content determination result can be expressed as(1.53±0.13)g/100 g(k=2).