内标校正气相色谱-质谱法测定空气PM_(2.5)中邻苯二甲酸二(2-乙基己基)酯的不确定度评定

Uncertainty evaluation for the determination of bis(2-ethylhexyl)phthalate in ambient air PM_(2.5)by gas chromatography mass spectrometry with internal standard correction

建立内标校正气相色谱-质谱法测定空气PM_(2.5)中邻苯二甲酸二(2-乙基己基)酯(DEHP)的不确定度评定方法,分析影响测量结果不确定度的因素,为提高检测结果质量提供依据。依据JJF 1059.1—2012《测量不确定度评定与表示》,建立数学模型,分析不确定度来源,评定各不确定度分量,计算合成标准不确定度和扩展不确定度。空气PM_(2.5)中DEHP的质量浓度为(0.306±0.020)μg/m^(3),k=2。测定结果的不确定度主要来源于采样体积、提取液测定和测量重复性,其中提取液测定引入的不确定度分量最大,采样体积和测量重复性引入的不确定度分量次之。

The uncertainty evaluation method for the determination of bis(2-ethylhexyl)phthalate(DEHP)in ambient air PM_(2.5)by gas chromatography-mass spectrometry with internal standard correction was established,and the factors affecting the uncertainty of measurement results were analyzed to provide basis for improving the quality of detection results.According to JJF 1059.1—2012 Evaluation and Expression of Uncertainty in Measurement,the measurement model was established to determine the source of uncertainty,each component of uncertainty were evaluated,and combined standard uncertainty and expanded uncertainty were calculated.The measurement result of DEHP in ambient air PM_(2.5)was(0.306±0.020)μg/m^(3),k=2.The uncertainty of the measurement results was mainly caused by the sampling volume,the determination of the extracting solution and the repeatability of measurement.The uncertainty component introduced by the determination of the the extracting solution was the largest,followed by the uncertainty component introduced by the sampling volume and the repeatability of measurement.