乳制品中非蛋白氮含量测定的不确定度评定

Evaluation of uncertainty in determination of non-protein nitrogen in dairy products

中文关键词:  乳制品  非蛋白氮  不确定度

英文关键词:dairy products  non-protein nitrogen  uncertainty

中文摘要:

      目的 建立滴定法测定乳制品中非蛋白氮含量的不确定度评定的方法。方法 根据中华人民共和国国家标准GB/T21704-2008《乳与乳制品中非蛋白氮含量的测定》和中华人民共和国国家计量技术规范JJF1059.1-2006《测定不确定度的评定与表示》建立不确定度模型, 运用《测量不确定度评定与表示指南》, 分析该方法测定中各不确定因素。结果 当乳制品中非蛋白氮的含量为0.0274%, 不确定度为0.000258%, 非蛋白氮含量表示为 [(0.0274±0.000258)%, K＝2]。结论 在确定的实验条件下, 本方法的不确定度主要来自于标定硫酸标准溶液和滴定非蛋白氮时对终点的判断, 同时测定非蛋白氮时的重复试验也是一个主要影响因素。

英文摘要:

      Objective To establish a titration assessment method for detecting the uncertainty of the non-protein nitrogen dairy. Methods The uncertainty model was established according to national standard of china GB/T21704-2008 “The determination of non-protein nitrogen content in milk and dairy products” and the National metrology technical specifications JJF1059.1-2006 “Evaluation and expression of uncertainty of measurement”, and the uncertainty factors in this method were analyzed by “Evaluation and Expression of Uncertainty in Measurement Guide”. Results When the non-protein nitrogen content in dairy products was 0.0274%, the uncertainty was 0.000258%, and the non-protein nitrogen content was expressed as [(0.0274±0.000258)%, K=2]. Conclusion Under determined experimental conditions, the major uncertainty sources are sulfuric acid standard solution, the judgment of the end point of titration and the repeat experiments of non-protein nitrogen.