氧化银沉淀消除基体中氯离子干扰的离子色谱法测定饮用水中氯代乙酸

Determination of Chloracetic Acids in Drinking Water by Ion Chromatography Using Silver Oxide as Precipitant Eliminating Interference of Chlorate in Matrix

建立了一种用氧化银作沉淀剂消除饮用水基体中大量氯离子干扰,以氢氧化钡作沉淀剂消除基体中大量硫酸根离子干扰;采用大体积进样的离子色谱法测定饮用水中氯代乙酸的新方法。此法不但能去除基体中大量氯离子、硫酸根离子,且不引入任何新的干扰。采用中高容量、疏水性较强的IonPac AS14HC阴离子色谱柱,使一氯乙酸和氯离子得到很好地分离。在进样量为500μL时,用NaOH溶液作为淋洗液,采用梯度洗脱,可在40min内同时测定3种卤代乙酸。一氯乙酸检出限为3.7μg/L;二氯乙酸检出限为3.6μg/L;三氯乙酸检出限为35.4μg/L。3种氯代乙酸的加标回收率均在91.5%～102%之间。

A method was developed for the simultaneous determination of mono-, di- and tri-chloroacetic acids in drinking water by ion chromatography with large volume direct injection, combined with a novel method that could eliminate interference of a large amount of chloride ion in matrix with silver oxide as precipitant and a large amount of sulfate ion in matrix with barium hydroxide as precipitant. With a medium high capacity, hydrophobic anion IonPac AS14HC column and sodium hydroxide as eluent, the three chloroacetie acid （CAAs） as well as chloride and sulfate could be separated well and determined within 40 min by gradient elution. A total of 500 uL sample loop was used. The detection limits for the three CAAs were 3.7 ug/L, 3.6 ug/L, 35.4 ug/L in turn. The spiked recoveries for the three CAAs were 91.5% - 102%.