李菊生，吴伟都*，杨杨，王雅琼，沈珊珊，薛玉清，李言郡，李正镕

（杭州娃哈哈集团有限公司，浙江省食品生物工程重点实验室，浙 江 杭州 310018）

摘要：本文应用凯氏定氮仪测定奶粉中蛋白质的含量，并对检测过程进行不确定来源分析，评价检测结果的不确定度。结果表明，当奶粉中蛋白质含量为23.55g/100g 时，在95％置信区间下其结果的扩展不确定度为0.32g/100g（k=2）。影响检测结果的各不确定度分量中，氮的系统回收、滴定所消耗硫酸标准溶液的体积及标准溶液的标定的准确度影响最大。

关键词：奶粉；蛋白质；不确定度评价；凯氏定氮仪

Uncertainty Evaluation for Determination of Protein in Milk Powder by Kjeldahl Nitrogen Analyzer

LI Ju-sheng，WU Wei-du*，YANG Yang，WANG Ya-qiong，SHEN Shan-shan，

XUE Yu-qing，LI Yan-jun，LI Zheng-rong

（Hangzhou Wahaha Group Company Limited，Key Laboratory of Food and Biological Engineering of ZhejiangProvince，Hangzhou 310018，China）

Abstract: In this paper，the protein content in milk powder was determined by Kjeldahl nitrogen determinationinstrument，and the source of uncertainty in the process of determination was analyzed，and the uncertainty of thedetection results was evaluated as well. The results showed that when the protein content in milk powder was 23.55g/100g，the expanded uncertainty of the result was 0.32g/100g（k=2） at the 95% confidence level. Among theuncertainty components that affected the test results，the systematic recovery of nitrogen，the volume of sulfuric acidstandard solution consumed by titration and the accuracy of calibration of standard solution had the greatest impact.

Key words: milk powder；protein；uncertainty evaluation；kjeldahl nitrogen analyzer

中图分类号：TS252.7           文献标志码：A                     文章编号：1007-7871（2023）05-0030-06

2023，Vol.26，No.5