气相色谱法测定饮用水中二氯乙酸和三氯乙酸含量的不确定度评定  

Evaluation of uncertainty in measurement of dichloroacetic acid and trichloroacetic acid in drinking water by gas chromatography

作　　者：李晓晶[1] 林玉娜[1] 甘平胜[1] 杨荣[1] 曾涛 刘苗[1] 罗晓燕[1] 潘心红[1] LI Xiao-jing;LIN Yu-na;GAN Ping-sheng;YANG Rong;ZENG Tao;LIU Miao;LUO Xiao-yan;PAN Xin-hong(Guangzhou Center for Disease Control and Prevention,Guangzhou 510440,China)

机构地区：[1]广州市疾病预防控制中心,广州510440

出　　处：《环境卫生学杂志》2022年第10期757-762,共6页JOURNAL OF ENVIRONMENTAL HYGIENE

摘　　要：目的 对气相色谱法测定饮用水中二氯乙酸和三氯乙酸含量的不确定度进行评定。方法 依据《测量不确定度评定与表示》(JJF 1059.1-2012)建立生活饮用水中二氯乙酸和三氯乙酸测定的数学模型,分析测定过程中各不确定度来源,评估饮用水中二氯乙酸和三氯乙酸含量测定的不确定度。结果 当饮用水中二氯乙酸和三氯乙酸含量为0.010 8和0.003 83 mg/L时,包含概率为95%,包含因子k=2,其扩展相对不确定的度分别为0.002 8和0.000 62 mg/L。结论 通过对不确定度的分析,发现标准曲线拟合残差是气相色谱法测定饮用水中二氯乙酸和三氯乙酸不确定度的主要来源,在测量时注意合理选择标准物质,准确配制标准溶液,做好标准曲线。Objective To evaluate the uncertainty in measurement model of dichloroacetic acid and trichloroacetic acid in drinking water by gas chromatography.Methods According to the Evaluation and Expression of Uncertainty in Measurement(JJF 1059.1-2012), a mathematical model was built to calculate the content of dichloroacetic acid and trichloroacetic acid in drinking water, and the sources and magnitudes of uncertainty in measurement were analyzed to evaluate the uncertainty in determining the content of dichloroacetic acid and trichloroacetic acid in drinking water.Results When the content of dichloroacetic acid and trichloroacetic acid in drinking water was 0.010 8 and 0.003 83 mg/L, respectively, the relative extended standard uncertainties were 0.002 8 and 0.000 62 mg/L, respectively, at a confidence level of 95% and a coverage factor of 2.Conclusion The curve fitting residual is the major source of uncertainty in gas chromatography-based measurement of dichloroacetic acid and trichloroacetic acid in drinking water.Rational selection of standard substance and accurate preparation of standard solution are key steps for a good standard curve.

关 键 词：气相色谱 二氯乙酸 三氯乙酸 饮用水 不确定度 

分 类 号：R113[医药卫生—公共卫生与预防医学]