基于控制图法评定苯系物标准样品中甲苯浓度的不确定度

Uncertainty Evaluation of Methylbenzene's Concentration in Standard Sample of Benzene Series Based on Control Chart Method

采用气相色谱法测定苯系物标准样品中甲苯的浓度并进行不确定度评定。依据《检测实验室中常用不确定度评定方法与表示》(控制图法)(GB/T 27411-2012)对检测结果进行不确定度的分析与量化。在期间精密度条件下,分析人员采用气相色谱法对苯系物标准样品进行测定并获得40个测量结果,对测量结果剔除异常值并验证其正态性和独立性后,建立指数加强移动平均值图(EWMA图),并用控制图法评定甲苯的测量不确定度。结果表明:在偏倚受控的期间精密度测量条件下,甲苯的扩展不确定度为±5.16 mg/L。

The concentration of methylbenzene in standard sample of Benzene series was determined by gas chromatography and then the uncertainty was evaluated.According to GB/T 27411-2012 Common Uncertainty Assessment Methods and Representations in Testing Laboratories(Control Chart Method),the uncertainty of the measurement results was analyzed and quantified.Under the condition of period precision,standard sample of Benzene series was determined by gas chromatography,and 40 measurement results were obtained.After eliminating the outliers and verifying the normality and independence,the exponentially weighted moving average chart(EWMA-chart)was established.The measurement uncertainty of methylbenzene was evaluated by the control chart method.The result showed that,under the condition of bias-controlled period precision measurement,the extended uncertainty of methylbenzene is±5.16 mg/L.