气相色谱法测定白酒中甲醇含量测量结果不确定度的评定

Uncertainty Evaluation for Determining Concentration of Methanol in Distilled Spirit by GC

[目的]建立气相色谱法测定白酒中甲醇含量的测量不确定度评定的数学模型。[方法]从测量程序各步骤评定不确定度的各项来源,对该方法所得结果的已识别来源的不确定度影响进行评价。[结果]测量结果不确定度主要来源于甲醇标准溶液、气相色谱仪定量重复性。当白酒中甲醇含量为0.072 g/L时,其扩展不确定度为0.006 6 g/L(K=2)。[结论]该研究可为评定白酒中甲醇含量的测量结果质量提供科学依据。

[ Objective ] A mathematical model was established to assess the uncertainty for determining the concentration of methanol in dis- tilled spirit by gas chromatography. [ Method] Various sources of uncertainty from the determination procedure were assessed. The influence of the identified uncertainty of the analytical result was evaluated. [ Result] The impacts of major source of measurement uncertainty.were metha- nol standard solution and the quantitative repeatability of GC. When the methanol content was 0. 072 g/L in distilled spirit, the expanded un- certainty reached 0. 006 6 g/L（ K = 2 ）. [ Conclusion ] The study can provide scientific basis for evaluating quality of methanol content in dis- tilled spirit.