密度瓶法复检配制酒中酒精度含量的不确定度分析

Uncertainty evaluation for the determination of alcohol content in re-test compound wine by pycnometric method

目的分析密度瓶法复检配制酒酒精度含量的各实验步骤产生的不确定度。方法以复检配制酒为研究对象,按照GB5009.225—2016《食品安全国家标准酒中乙醇浓度测定》的第一法密度瓶法的要求,并根据CNAS-GL06《化学分析中不确定度的评估指南》、JJF 1059.1—2012《测量不确定度评定与表示》,测得复检配制酒酒精度含量的不确定度。结果在95%的置信区间下,复检配制酒的酒精度测量结果为(10.18±0.14)%vol, k=2。结论密度瓶法测定复检配制酒的不确定度主要来源为样品的复杂性、密度瓶温度计校准和测量重复性引入的随机效应。

Objective To analyze the uncertainty generated by each experimental step in the retesting of alcohol content of compound wine by pycnometric method.Methods According to GB 5009.225—2016“Determination of Ethanol Concentration in National Standard for Food Safety”,alcohol content in re-test compound wine was determined by pycnometric method,and according to CNAS-GL06“Guidance on Quantifying Uncertainty in Chemical Analysis”,JJF1059.1—2012“Evaluation and Expression of Measurement Uncertainty”,the uncertainty evaluation for determination of alcohol content in re-test compound wine was measured.Results Under the 95%confidence internal,the measurement result of alcohol content in re-test compound wine was(10.18±0.14)%vol,with the expansion factor k=2.Conclusion The main sources of uncertainty in the determination of retested liquor by pycnometric method are the complexity of sample,the random effect introduced by the calibration of density bottle thermometer and the measurement repeatability.