自来水中卤乙酸的液-液萃取气相色谱测定法

Determination of Haloacetic Acids,Disinfection By-products,in Drinking Water by Gas Chromatography with Liquid-Liquid Extraction Technology

目的建立自来水中消毒副产物卤乙酸(haloacetic acid,HAAs)的液-液萃取气相色谱测定法。方法以甲基叔丁基醚为萃取溶剂,1,2-二溴丙烷为内标,在酸性条件下加10 g无水硫酸钠强化萃取。取醚层加入甲醇溶液,于酸性条件下,在50℃水浴中酯化反应1 h。采用气相色谱法进行检测。结果在0.35～100.0μg/L线性范围内,该方法所得一溴乙酸、二氯乙酸、三氯乙酸和二溴乙酸的回归方程均呈良好的线性关系,r≥0.999;检出限分别为1.30、0.85、0.35、0.75μg/L。该方法所得的平均回收率为75.6%～99.8%,RSD为4.3%～7.8%。结论该方法操作简便快捷,灵敏度和准确度均较高,适用于自来水中消毒副产物卤乙酸的测定。

Objective To establish a method for the determination of haloacetic acid （HAAS） in drinking water by gas chromatography with liquid-liquid extraction technology. Methods Methyl tert-butyl ether and 1,2-dibromide propane was used as extraction solvent and an internal standard, respectively. Under acidic conditions, intensive extraction was conducted by adding Na2SO4 （10 g） to samples. Adding methanol to ether layer,the esterification reaction was conducted for 1 h at 50 ℃ in acidic conditions. The obtained product was detected by gas chromatography. Results The developed method displayed a wider linear range from 0.35 to 100.0 μg/L with the correlation coefficients more than 0.999,and the limit of detection was 1.30,0.85,0.35 and 0.75 μg/L respectively. The ranges of average recovery were 75.6%-99.8% ,and relative standard deviations （RSDs） were 4.3%-7.8%.Conclusion The present method is simple,sensitive, accurate and applicable to the determination of haloacetic acid in drinking water.