顶空-气相色谱法测定水中苯系物的不确定度研究

Evaluation of Uncertainty in Determining BTEXs in Water by Headspace Gas Chromatography

建立顶空-气相色谱法测定水中苯系物不确定度的评定方法,分析测定过程中的主要影响因素,评定测定过程中引入不确定度的来源.通过分析和量化影响测定结果的不确定度分量,得出各分量对不确定度的相对贡献,对测定结果进行了表述.结果表明,顶空-气相色谱法测定水中苯系物七种组分的相对合成不确定度范围为6.09％ ∽ 11.11％,苯乙烯和邻二甲苯的不确定度较大,不确定度的主要影响因素为标准溶液及曲线配制、方法加标回收和样品重复测量.

This paper established a method for evaluating uncertainty of BTEXs measurement in water by Headspace - Gas Chromatography. The sources of uncertainty and main influential factors of uncertainty in the measurement process were also ana- lyzed. According to the analysis and quantification on factors impacting the uncertainty, the standard uncertainty and the expand- ed uncertainty were calculated. The result showed that the relative combined uncertainty range was 6. 09% - 11.11% in the measurement of the seven BTEXs components in water by Headspace - Gas Chromatography. The uncertainty of styrene and o - xylene was higher than that of the others. The main influential factors of uncertainty were the calibration of standard curve, the re- coveries of sample and samples repeatability.