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目的以二氯甲烷、二氯乙烷、三溴甲烷等为例,讨论顶空参数对顶空气相色谱法测定生活饮用水中卤代烃混合物的影响。方法以达到气液平衡时的响应值对顶空过程中的顶空温度和平衡时间进行交叉试验,比较其在不同的顶空条件下的灵敏度、最低检出限、线性回归等指标。结果在不同的顶空条件下,其标准线性回归和截距相差不大。从可行性分析,并经过各指标的比较,最终确定了最佳的顶空条件:顶空温度为60℃;平衡时间为30 min。与国家标准方法所采用的顶空处理相比,增加了可操作性,提高了分析的灵敏度,降低了最小检出限,同时也大大缩短了分析周期。结论优化后的顶空条件可以满足同时测定多种卤代烃的顶空分析的应用。
Objective To discuss the influence of headspace parameters on the determination of halohydrocarbon mixtures in domestic drinking water by headspace gas chromatography with methylene chloride, dichloroethane and tribromomethane as examples. Methods The cross-over test of headspace temperature and equilibrium time in the process of headspace was performed with the response value of gas-liquid equilibrium. The sensitivity, minimum detection limit and linear regression were compared under different headspace conditions. The results of different headspace conditions, the standard linear regression and intercept little difference. From the feasibility analysis and comparison of various indexes, the best headspace condition was finally determined: the head space temperature was 60 ℃ and the equilibrium time was 30 min. Compared with the headspace treatment adopted by the national standard method, the operability is increased, the sensitivity of the analysis is increased, the minimum detection limit is reduced, and the analysis cycle is greatly shortened. Conclusion The optimized headspace conditions can be used to determine the headspace analysis of a variety of halogenated hydrocarbons simultaneously.