顶空-气相色谱法测定白砂糖中二氧化硫残留量的不确定度评定

Determination of white granulated sugar by headspace-gas chromatography uncertainty assessment of sulfur dioxide residue

评定顶空-气相色谱法测定白砂糖中的二氧化硫残留量的不确定度,找出对检测结果影响最大的因素,讨论此方法检测的可靠性。建立数学模型,采用JJF 1059.1-2012《测量不确定度与表示》对其进行分析与评定。结果显示,测定白砂糖二氧化硫的含量为5.92 mg/kg的结果的不确定度U(x)=0.18 mg/kg(k=2)。表明该方法与酸碱滴定法和比色法相比,都具有较小不确定度范围,适用于白砂糖中二氧化硫的检测。对检测结果影响较大的是重复性与回收率,增加检测次数与使用回收率校正可以增加检测结果的准确性。

To evaluate the uncertainty of determination of sulfur dioxide residue in white granulated sugar by headspace-gas chromatography,to find out the most influential factors,and to discuss the reliability of this method.A mathematical model was established,and the measurement uncertainty and representation of JJF 1059.1-2012 was used to analyze and evaluate the model.The results showed that the uncertainty U(x)=0.18 mg/kg(k=2)for determination of sulfur dioxide content in white granulated sugar was 5.92 mg/kg.It is shown that the method compared with acid-base titration and colorimetric method,it has a smaller uncertainty range and is suitable for the determination of sulfur dioxide in white granulated sugar.Repeatability and recovery rate have great influence on detection results.Increasing detection times and using recovery rate correction can increase the accuracy of detection results.