气相色谱内标法测定白酒中甲醇的不确定度评定

Evaluation of Uncertainty in Measurement of Methanol in Liquor by Gas Chromatographic Internal Standard Method

利用气相色谱内标法对白酒中的甲醇含量进行测定,对测量结果进行不确定度评定。依据JJF 1059. 1—2012《测量不确定度评定与表示》建立数学模型,分析实验过程中各不确定度来源,计算各不确定度分量,进而评定气相色谱内标法测定白酒中甲醇的不确定度。经检测白酒中甲醇含量为89. 7 mg/L,计算得其扩展不确定度为13. 5 mg/L(包含因子k=2)。结果表明,标准曲线的线性回归是影响该方法不确定度产生的主要因素。在测定时应加强这方面的控制,从而提高测量结果的准确性。

The content of methanol in liquor was measured by using gas chromatographic internal standard method.The uncertainty of measurement result was evaluated.Based on JJF 1059.1-2012 "Evaluation and Expression of Uncertainty in Measurement",a mathematic model was established to analyze the sources of uncertainty and calculate the uncertain components during the experiment process.The model was used to assess the uncertainty of the internal standard method to measure the methanol in liquor.The content of methanol in liquor was 89.7mg/L,and the extended uncertainty was 13.5mg/L (including factor k=2).The main factor influencing the uncertainty of this method was the linear regression of the standard curve.The control on the standard curve should be reinforced in order to improve the accuracy of determination.