固相萃取-气相色谱法测定自来水中氯乙酸

DETERMINATION OF DICHLOROACETIC AND TRICHLOROACETIC ACIDS IN TAP WATER BY USING GAS CHROMATOGRAPHY WITH THE ELECTRON CAPTURE DETECTOR

目的：为自来水中氯乙酸的监测提供灵敏而可靠的实验方法.方法：样品经D101大孔树脂富集和乙腈洗脱,用10%硫酸-甲醇将目标化合物衍生成相应的甲酯,甲基叔丁醚萃取,GC-ECD测定.结果：本法对自来水的加标回收率在87.9%～101.3%之间,5份平行样品测定的相对标准偏差（RSD）二氯乙酸为3.78%,三氯乙酸为5.27%,检出限依次为0.14ng和0.03ng.结论：所建立的方法快速、简便、准确,能满足自来水中目标化合物定量测定的要求.

Objective： To develop a sensitive and reliable method for the determination of dichloroacetic and trichloroacetic acids in tap water. Methods： The analyte was preconcentrated with D101 macroporous resin colurnn and eluted with acetonitrile by the combination of the static and dynamic elution. The target compounds were esterified with 10 % sulfuric acid - methanol solution and the products were extracted with methyl - text - butyl ether and determined by gas chromatography with the electron capture detector. Results： The proposed method was applied to tap water with the recovery in the range of 87.9% - 101,3%. The relative standard deviation of sample （n= 5） was 3,78% for dichloroacetic acid and 5.27% for trichloroacetic acid and the detection limit was 0.14 ng and 0.03 ng respectively. Conclusion： The proposed method was sensitive and precise for the determination of target oomponnds in tap water.