In(OH)_3共沉淀-电感耦合等离子体质谱法测定海水中的稀土元素

Determination of rare earth elements in seawater by inductively coupled plasma-mass spectrometry with pre-concentration of In(OH)_3 co-precipitation

采用In(OH)_3共沉淀法对海水中稀土元素进行富集,并将该方法与电感耦合等离子体质谱法联用实现对海水中15种稀土元素的同时测定。通过优化实验,得出最佳的共沉淀条件为:溶液的pH值控制在8.5～9.5之间、共沉淀剂InCl3的浓度为40 mg/L、共沉淀时间最终选择为30 min。在最佳条件下,测定的稀土元素校正曲线的相关系数均在0.999 9以上,检出限为0.05～0.45 ng/L。对实际海水样品平行测定6次,并进行低、中、高3个浓度水平的添加回收试验,各元素相对标准偏差(RSD)均小于7.70%,回收率在86.0%～106.0%之间。该方法在测试过程中采用百里酚蓝指示液替代pH计对测试液进行pH值监控,具有操作简单、检测快速、精密度和准确性良好等优点,可满足海水样品中的痕量稀土元素定量分析的要求。

In(OH)3 co-precipitation was used to enrich the rare earth elements(REEs)from seawater,which was combined with inductively coupled plasma-mass spectrometry(ICP-MS)to determine determinate simultaneously 15 kinds of REEs in seawater.The optimum conditions for co-precipitation were 40 mg/L InCl3 at pH 8.5-9.5 when the precipitation time was 30 min.The correlation coefficient of calibration curves for determination of REEs is higher than 0.999 9,and the limit of detection 0.05-0.45 ng/L.According to the 6 replicate determinations of actual seawater samples,the standard added recoveries and relative standard deviations of REEs was 86.0%-106.0%and lower than 7.70%.In this work,thymol blue indicator solution was used to replace pH meter to monitor the pH value testing sample.This method possessed the advantages of simple operation,rapid determination,good precision and accuracy,and therefore can be used for determination of trace REEs in seawater.