GB/T 5750.8—2023顶空-气相色谱法测定饮用水中三氯甲烷和四氯化碳的问题与建议

Problems and Suggestions of GB/T 5750.8—2023 for Determination of Chloroform and Carbon Tetrachloride in Drinking Water by Headspace-Gas Chromatography

对GB/T 5750.8—2023中的顶空-气相色谱法测定生活饮用水中三氯甲烷和四氯化碳方法确认中影响定量准确性的因素,如分流比、色谱柱、基质空白、标准曲线配制等进行了讨论,并结合实验室的7697A顶空自动进样器、7890B气相色谱仪及所用DB-1701石英毛细管柱(30 m×0.25 mm×0.25μm)对方法进行了条件优化.采用优化后的试验条件对方法进行了确认.结果表明,三氯甲烷和四氯化碳分别在质量浓度为0.1~10.0μg/L和0.01~1.0μg/L范围内线性良好,检出限分别为0.025和0.0020μg/L,定量限分别为0.083和0.0067μg/L,相关系数r均大于0.999,相对标准偏差分别为4.2%~6.5%和1.8%~4.0%,加标回收率分别为96.8%~102.5%和104.0%~107.2%.优化后的方法可满足生活饮用水中三氯甲烷和四氯化碳的测定要求,为水中三氯甲烷和四氯化碳含量相关测试提供参考.

The factors affecting the quantitative accuracy of GB/T 5750.8—2023 for the determination of chloroform and carbon tetrachloride in drinking water by headspace-gas chromatography,such as split ratio,chromatography column,matrix blank and standard curve preparation,etc.,were discussed.And the conditions were optimized by combining with the 7697A headspace autosampler,the 7890B gas chromatograph and the DB-1701 quartz capillary column(30 m×0.25 mm×0.25μm).The method was confirmed by the optimized experimental conditions,and the linearities of chloroform and carbon tetrachloride were good in the range of 0.1~10.0μg/L and 0.01~1.0μg/L,respectively.The limits of detection were 0.025 and 0.0020μg/L,the limits of quantification were 0.083 and 0.0067μg/L,respectively.And the correlation coefficients were greater than 0.999,the relative standard deviations were 4.2%~6.5%and 1.8%~4.0%,and the recoveries were 96.8%~102.5%and 104.0%~107.2%,respectively.The optimized method can meet the requirements for the determination of chloroform and carbon tetrachloride in drinking water,and provide a reference for the testing of trichloromethane and carbon tetrachloride in water.