质量控制和方法确认数据评定车用汽油中苯含量的不确定度

Uncertainty of benzene content in vehicle gasoline evaluated by quality control and method confirmation data

采用气相色谱法对车用汽油中的苯含量进行测定,利用质量控制和方法确认数据对测量结果进行不确定度评定。在期间精密度测量条件下,分别对精密度不确定度分量和偏倚不确定度分量进行分析,在整个测量系统处于受控状态下进行不确定度评定。结果表明,偏倚不确定度分量大于期间精密度的不确定度分量,是苯含量测量不确定度的主要分量;当苯含量测量结果为0.8%(ν/ν)时,在包含概率为95%的条件下,扩展因子为2,苯含量测量结果不确定度可表示为(0.8±0.05)%。在期间精密度测量条件下,基于质量控制结果和方法确认数据,合并两者带来的累积效应,作为不确定度的估计量评定车用汽油中苯含量不确定度,为广大化学分析工作者提供一种评估车用汽油中苯含量测量不确定度的方法。

The benzene content in automotive gasoline was determined by gas chromatography, and the uncertainty of measurement results was evaluated by quality control and method confirmation data. Under the condition of time precision measurement, the uncertainty components of precision and bias were analyzed respectively, and the uncertainty of the whole measurement system was evaluated under the controlled state. The results showed that the bias uncertainty component was more than the uncertainty component of the period precision, and it was the main component of the uncertainty of benzene content measurement. When the measurement result of benzene content was 0.8%(ν/ν), the expansion factor was 2 under the condition of 95% inclusion probability, and the uncertainty of the measurement result of benzene content can be expressed as (0.8+0.05)%. Under the condition of time precision measurement, based on the quality control results and method confirmation data, the cumulative effect of the two methods is combined to evaluate the uncertainty of benzene content in automotive gasoline as an estimator of uncertainty, which provides a method for the majority of chemical analysts to evaluate the uncertainty of benzene content measurement in automotive gasoline.