饮用水中卤代乙酸分析方法研究

Analysis of Halocaetic Acids in Drinking Water

本文在研究了分析饮用水中的三种卤代乙酸 (HAA3)〔一氯乙酸 (MCCAA)、二氯乙酸 (DCAA)、三氯乙酸(TCAA)〕液 -液萃取衍生气相色谱法的多种条件影响后 ,提出了在酸性条件下 ,以含 1,2 -二溴丙烷 (1,2 -DBP)内标的甲基叔丁基醚 (MtBE)萃取 ,萃取液用 10 %硫酸甲醇溶液衍生 2h ,再用饱和碳酸钠中和 ,然后通过气相色谱 (常用柱HP -5 ,电子捕获检测器ECD)分离检测。本法检出限为MCAA10 μg/L ,S/N >10 ;DCAA12 μg/L ,S/N >80 ;TCAA4μg/L ,S/N >10 0 ;自来水样加标回收率为 86 %～ 110 %。

A modified analytical method of haloacetic acids in drink ing water was presented. The optimizing conditions (derivative time, internal st andard (IS), GC column and analysis condition) were described. The method includ ed following procedures: The sample was extracted with methyl tertiary-butyl eth er (MTBE) at an acidic pH. Sodium sulfate is added to increase extraction effici ency, and the extracted compounds are methylated in two hours with 10% H 2SO 4 /CH 3OH solution to product methyl ester that can be analyzing by temperature -programmable capillary column gas chromatography with an electron capture detec t or (ECD). Recovery ratio range is from 86% to 110%,the R^2(n=5) of the standard curves of monochloroacetic acid, dichloroacetic acid and trichloroacetic acid a re 0.9974,0.9948,0.9869,and the method detection limit (MDL) are MCAA 10μg/L (S /N￡3/410)￡?DCAA12|ìg/L(S/N￡3/480),TCAA4|ìg/L(S/N￡3/4100).