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目的从标准曲线制作及样品加标方法两方面对现有顶空毛细管气相色谱测定饮用水中三氯甲烷、四氯化碳的方法加以改进,以解决实际检验工作中常遇到的方法线性差、回收率不准确的问题。方法省略繁琐的容量瓶稀释法,直接使用微量注射法吸取低浓度三氯甲烷、四氯化碳混合标准物质至装有一定量纯水或样品的顶空瓶中,进行标准系列配制及样品加标,以顶空毛细管气相色谱法测定。结果三氯甲烷、四氯化碳线性范围分别为6.0～60μg/L和0.02～0.2μg/L,相关系数为0.999 5～0.999 9和0.999 0～0.999 5,回收率分别为91.0%～107.9%和92.5%～107.5%,检出限为0.007和0.000 7μg/L,精密度分别为2.9%、7.3%。结论该方法适用于饮用水中三氯甲烷、四氯化碳的测定,且具有良好的线性关系、准确度和精密度。
OBJECTIVE To improve the method of determination of trichloromethane and carbon tetrachloride in drinking water by headspace capillary gas chromatography from two aspects of standard curve preparation and sample spike method in order to solve the problems of poor linearity in the actual inspection work, Recovery rate is not accurate. Methods omitting cumbersome method of volumetric flask dilution method, the direct use of micro-injection method to draw low concentrations of chloroform, carbon tetrachloride mixed standard material containing a certain amount of pure water or sample headspace bottles, the standard series of preparation and sample spiking , As determined by headspace capillary gas chromatography. Results The linear ranges of trichloromethane and carbon tetrachloride were 6.0 ~ 60μg / L and 0.02 ~ 0.2μg / L respectively, the correlation coefficients were 0.999 5 ~ 0.999 9 and 0.999 0 ~ 0.999 5, the recoveries were 91.0% ~ 107.9% And 92.5% -107.5% respectively. The limits of detection were 0.007 and 0.000 7 μg / L respectively, with the precision of 2.9% and 7.3% respectively. Conclusion The method is suitable for the determination of trichloromethane and carbon tetrachloride in drinking water with good linearity, accuracy and precision.