生活饮用水中三氯甲烷和四氯化碳自动顶空气相色谱法测定方法的改进

Improvement on Determination Method of Trichloromethane and Carbon Tetrachloride by AHGC in Drinking Water

目的:建立改进生活饮用水中三氯甲烷和四氯化碳自动顶空气相色谱测定方法。方法:采用顶空气相色谱测定法和PE-Turbo Matrix-40顶空自动进样系统,色谱条件为载气(氮气),流量为2.0 mL/min,柱温为40℃,保持5.5 min,以15℃/min升温至85℃,保持1 min;进样口温度为250℃,检测器温度为300℃,分流比为30∶1,测定饮用水中三氯甲烷和四氯化碳的含量。结果:三氯甲烷浓度在2.0~32.0μg/L和三氯甲烷浓度在0.2~3.2μg/L范围内呈良好的线性关系,相关系数分别为0.999 5和0.999 7;检出限分别为0.045μg/L和0.008μg/L;回收率分别为98.5%~100.6%和98.75%~101.5%范围内,平均RSD分别为3.07和2.48,测得三氯甲烷0.055 4 mg/L和三氯甲烷<0.000 1。结论:改进后方法的操作简单、快速、灵敏度高、重复性和准度性更好,可应用于生活饮用水样中三氯甲烷和四氯化碳的含量测定。

Objective： To establish an improvement of determination of trichloromethane and carbon tetrachloride by automatic headspace gas chromatography（AHGC） in drinking water. Methods： Using automatic headspace gas chromatography（AHGC） and PE-Turbo Matrix-40 headspace automatic sampling system, the flow rate of carrier gas（nitrogen）was 2.0 mL/min, column temperature was maintained at 40 degrees centigrade, 5.5 min was maintained at 15 centigrade to85, and 1 min was maintained; the inlet temperature was 250 ℃, the temperature of the detector was 300 ℃, the ratio of distributary was 30：1 and contents of chloroform and tetrachloride in drinking water were measured. Results： The concentration of trichloromethane was between 2.0 μg/L and 32.0 μg/L and trichloromethane concentration was betwee 0.2 μg/L and 3.2 μg/L showing a good linear relationship. The correlation coefficients were 0.999 5 and 0.999 7, and the detection limits were 0.045 μg/L and 0.008 μg/L, respectively. The recovery rates were between 98.5% and 100.6%, and 98.75% and101.5%, and the average RSD was 3.07 and 2.48, respectively. Trichloromethane 0.055 4 mg/L and trichloromethane0.000 1 were measured. Conclusion： The method is simple, fast, sensitive, reproducible and accurate, and It can be applied to the determination of trichloromethane and carbon tetrachloride in drinking water samples.