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目的建立同时测定生活饮用水中5种挥发性卤代烃的自动顶空毛细管柱气相色谱方法。方法对自动顶空条件进行优化,包括顶空样品瓶加热温度、样品瓶平衡时间、液气比和Na Cl加入量;水中的微量卤代烃经自动顶空提取后,进气相色谱仪,采用HP-5毛细管色谱柱,ECD检测器进行检测,以保留时间定性,外标法定量。结果最佳顶空条件:样品瓶平衡时间为20 min,液气比为1∶1,顶空样品瓶加热温度为70℃,进样针温度为80℃,传输线温度为90℃,Na Cl加入量为3 g;三氯甲烷、四氯化碳、三氯乙烯、四氯乙烯、三溴甲烷的线性浓度范围分别为0.498~49.80、0.242~24.2、0.497~49.70、0.247~24.70、0.493~49.30μg/L;检出限为0.1~0.2μg/L,平均加标回收率为91.1%~100.0%,RSD为2.4%~4.1%。结论所建立的分析方法简便、灵敏、快速、准确,可同时测定生活饮用水中多种挥发性卤代烃。
Objective To establish an automatic headspace capillary gas chromatographic method for simultaneous determination of five volatile halohydrocarbons in drinking water. Methods The conditions of automatic headspace were optimized, including the heating temperature of headspace sample vial, equilibration time of sample vial, the ratio of liquid to gas and the content of NaCl. The trace amount of halogenated hydrocarbons in water was extracted by automatic headspace, then into gas chromatograph, Using HP-5 capillary column, ECD detector for detection, retention time qualitative, external standard method. Results The optimal headspace conditions were as follows: the equilibrium time of sample vial was 20 min, the liquid-gas ratio was 1: 1, the temperature of headspace vial was 70 ℃, the temperature of needle was 80 ℃ and the temperature of transfer line was 90 ℃. The linear range of the concentrations of trichloromethane, carbon tetrachloride, trichlorethylene, tetrachlorethylene and tribromomethane were 0.498 ~ 49.80, 0.242 ~ 24.2, 0.497 ~ 49.70, 0.247 ~ 24.70, 0.493 ~ 49.30μg / L; the detection limit was 0.1 ~ 0.2μg / L, the average recovery was 91.1% ~ 100.0%, RSD 2.4% ~ 4.1%. Conclusion The established analytical method is simple, sensitive, rapid and accurate, and can simultaneously determine a variety of volatile halogenated hydrocarbons in drinking water.