全自动凯氏定氮仪测定蛋白质(以N计)不确定度分析与探讨

目的:用全自动凯氏定氮仪测定蛋白质(以N计)不确定度进行分析与探讨。方法 :采用GB 5009.5-2016第一法凯氏定氮法测定蛋白质(以N计)含量,建立数学模型,通过对各个不确定度分量的计算合成,找出影响测量不确定度的因素,最终得出样品中蛋白质(以N计)含量的扩展不确定度与合成标准不确定度。结果:蛋白质(以N计)含量测定的扩展不确定度为(20.93±0.25)%,k=2。结论:采用JJF 1059.1-2012《测量不确定度评定与表示》,对不确定度进行评定,确保蛋白质(以N计)含量结果的准确性。

Uncertainty analysis of protein content determination with automatic Kjeldahl nitrogen analyzer

Using the first method of GB 5009.5-2016, Kjeldahl nitrogen method, to determine the content of protein(in terms of N), and a mathematical model is built. Through the calculation and synthesis of each uncertainty component, the factors affecting the measurement uncertainty are found out. Finally, the expanded uncertainty and synthetic standard uncertainty of the protein(in terms of N) content in the samples are obtained. The expanded uncertainty of the determination of protein(in terms of N) is(20.93±0.25) %, k=2. According to JJF 1059.1-2012 Evaluation and Expression of Measurement Uncertainty, the uncertainty is evaluated to ensure the accuracy of protein content(in terms of N) test results.