顶空气相色谱法测定水中卤代烃不确定度的评定

An evaluation on the uncertainty in determination of halogenated hydrocarbon in water by headspace gas chromatography

目的建立生活饮用水中7种挥发性卤代烃含量检测结果的不确定度。方法用顶空气相色谱法测定生活饮用水中7种挥发性卤代烃的含量,从测定程序分析测量不确定度的来源,并对产生的不确定度各分量进行分析。结果当水样中含三氯甲烷12.95μg/L、四氯化碳0.51μg/L、三氯乙烯5.42μg/L、四氯乙烯4.99μg/L、一氯二溴甲烷4.95μg/L、二氯一溴甲烷2.66μg/L和三溴甲烷10.17μg/L时,其扩展不确定度分别为2.13、0.08、0.81、0.71、0.92、0.54和1.30μg/L(k=2)。结论影响顶空气相色谱法测定生活饮用水中7种挥发性卤代烃不确定度的因素主要是测量的重复性、标准使用液的配制、标准工作曲线拟合和样品回收率所产生的误差。

Objective To evaluate the uncertainty in determining the concentration of seven kinds of halogenated hydrocarbon in drinking water. Methods Headspace gas chromatography was used to determinate seven kinds of halogenated hydrocarbon in drinking water. The causes of uncertainty from the program were analyzed and each component of uncertainty was calculated. Results As the concentration of trichloromethane, carbon tetrachloride, trichloroethylene, tetrachloroethylene, dibromochloromethane and bromoform in water were 12. 95,0. 51,5.42,4. 99,4. 95,2. 66 and 10. 17 μg/L, respectively, the expanded uncertainty of them were 2. 13, 0. 08, 0. 81, 0. 71, 0. 92, 0. 54 and 1.30 μg/L（k =2）, respectively. Conclusion The major factors that influence the uncertainty of determining the seven kinds of halogenated hydrocarbon in drinking water by headspace gas chromatography are repeated sample measurement, standard working curve fitting and errors from sample recovery.