柱后衍生离子色谱法同时测定瓶装水中的碘酸根、亚氯酸根和溴酸根

水中的碘酸根、亚氯酸根和溴酸根是重要的消毒副产物,主要通过大体积浓缩后直接电导检测,或通过柱前或柱后化学反应将目标物转化成容易检测的物质后检测。本方法采用大体积进样柱后衍生紫外检测的分析方法,通过条件优化获得了较高的灵敏度和信噪比。利用一套自动分析系统,可以满足饮用水中痕量碘酸根、亚氯酸根、溴酸根的同时监测。碘酸根、亚氯酸根和溴酸根的检出限分别为0.5,0.4,0.1 μg/L。对于不同的加标样品,碘酸根、亚氯酸根和溴酸根的回收率分别为70.8%~98.0%,92.4%~100%和93.2%~104.1%。该方法应用于北京市场上的瓶装饮用水分析,结果显示瓶装纯净水中的碘酸根、亚氯酸根、溴酸根浓度均低于检出限,而瓶装矿泉水中碘酸根、溴酸根的最高含量分别达到9.4 μg/L和78.4 μg/L。

Simultaneous Determination of Iodate, Chlorite and Bromate in Bottled Drinking Water by Ion Chromatography with Post-Column Reaction and UV Detection

Iodate, chlorite and bromate in bottled water are disinfectant by-products (DBPs) from ozonation. The established methods for simultaneous determination of iodate, chlorite and bromate are mostly based on pre- or post-column chemical reaction in which the target compound was converted to another easily detectable species. However, the procedure suffers from several time-consuming reaction steps that involve multiple chemicals, or where the reagents themselves are toxic. In the present study, a rapid, highly sensitive, precise and accurate method was established, and a post-column reaction with sodium nitrite and acid solution of potassium bromide was employed to enhance sensitivity and to reduce interferences. Under optimized conditions, the method limits for iodate, chlorite and bromate were 0.5, 0.4 microg/L and 0.1 microg/L, respectively. Percentage recoveries of iodate, chlorite and bromate varied from 70.8% to 98.0%, 92.4% to 100% and 93.2% to 104.1% respectively with different spiked water samples. The proposed method was demonstrated for detecting the concentrations of iodate, chlorite and bromate in bottled water produced from different water sources. Results showed that severe bromate contamination was present in bottled mineral water purchased from Beijing supermarket, which used spring water or ground water as the sources.