循环离子色谱法测定生活饮用水中的痕量溴酸盐

Determination of trace bromate in drinking water by cyclic ion chromatography

目的构建基于阀切换技术的循环离子色谱系统,用于测定生活饮用水中痕量的溴酸盐。方法利用离子色谱KOH淋洗液在经过抑制器后转化为水失去洗脱能力的原理,采用KOH溶液梯度洗脱和阀切换的方式,来在线消除样品中高浓度氯离子基体对溴酸盐测定的干扰。实现了水样中痕量溴酸根的准确定量。以保留时间定性,外标法定量。结果在优化的色谱和切换条件下,通过对溴酸盐的循环测定,消除了水样中氯离子的干扰。方法进样量为500μl,线性范围为1.0μg/L~50μg/L,以3倍信噪比的方法算得检出限为0.3μg/L,精密度实验得高中低三个浓度水平的相对标准偏差均≤4.8%方法相对标准偏差在3.2%~4.8%,平均回收率为97.3%~102.7%;干扰实验显示,样品中共存的无机阴离子对溴酸盐的测定无干扰。结论该法操作简单,准确度和精密度良好,适用于饮用水中痕量溴酸盐的准确测定。

Objective A cyclic ion chromatographic system based on valve-switching was established for the determination of trace bromate in drinking water.Methods Based on the principle that the KOH eluent of ion chromatography can be transformed into water after passing through the suppressor and loses its elution ability,gradient elution of KOH solution and valve switching technology were adopted to online eliminate the interference of chloride ion matrix during bromate determination,and accurate determination of trace bromate was realized.Retention time was used for qualitative analysis,and the external standard curve method was used for quantitation.Results Under the optimized chromatographic and switching conditions,the influence of chloride ion on the determination of bromate was eliminated by cyclic determination of bromate.The injection volume of this method was 500μl,and the linear range was 1.0μg/L-50μg/L,the limit of detection was 0.3μg/L based on the S/N=3.The relative standard deviations of the three concentration levels of high,medium and low in the precisionexperiment were all≤4.8%,and the average recoveries were 97.3%-102.7%.The interference experiment showed that the coexisting inorganic anions in the sample had no interference with the determination of bromate.Conclusion This method has the advantages of simple operation,good accuracy and precision,and is suitable for the accurate determination of trace bromate in drinking water.