强酸性阳离子交换纤维富集-电感耦合等离子体原子发射光谱法测定水系沉积物中稀土元素

Determination of rare earth elements in aquo-system sediments using inductively coupled plasma atomic emission spectrometry after enrichment with strong acid cation exchange fiber

对聚丙烯基强酸性阳离子交换纤维分离富集痕量稀土元素La，Nd，Eu，Gd，Er和Yb及其电感耦合等离子体原子发射光谱（ICP-AES）测定进行了研究。优化了纤维柱吸附和洗脱稀土元素的条件，pH3的稀土待富集试液以6-14mL／min流速上柱，以流速为1．5-4．0mL／min的10mL 2．5mol／L HNO3洗脱后，用ICP-AES测定。在洗脱前用0.5mol／L HNO3预淋洗，可将大部分K，Na，Mg，Ca，Ba，Cu，Zn，Fe和A1等共存元素除去，而不影响稀土元素的回收率。分析方法的检出限为La 0.016ng／mL，Nd 0．051ng／mL，Eu 0．006ng／mL，Gd 0．029ng／mL，Er 0．048ng／mL，Yb 0．006ng／mL。富集和测定了单纯水样和合成水样中的La，Nd，Eu，Gd，Er和Yb等稀土元素，它们的回收率为88．0％-110％，相对标准偏差为0．3％-2．7％；富集和测定了水系沉积物国家标准物质（GBW07311）中这6种稀土元素，结果与认定值吻合，相对标准偏差为1．1％-5．2％。

The separation and enrichment of trace rare earth elements including La, Nd, Eu, Gd, Er and Yb with polypropylene radical strong acid cation exchange fiber and determination by inductively coupled plasma atomic emission spectrometry （ICP-AES）were studied. Under optimizing the condi- tions, rare earth elements were sorbed at column completely when test solution was pH 3 and the flow rate is between 6 and 14 mL/min. The coexisting elements of K, Na, Mg, Ca, Ba, Cu, Zn, Fe and AI could mostly be removed by pre-eluting with 0.5 mol/L HNO3, and then rare earth elements could be eluted quantitatively with 10 mL of 2.5 mol/L HNO3. The detection limit of the method is as follow： 0.016 ng/mL for La, 0.051 ng/mL for Nd, 0.006 ng/mL for Eu,0.029 ng/mL for Gd, 0.048 ng/mL for Er, 0.006 ng/mL for Yb. The recoveries for those rare earth elements in simple water and synthetic water samples were in the range of 88.0%-110%, and the RSDs were between 0.3% and 2.7%. A aquo-system sediments standard reference material （GBW07311）was used to evaluate the accuracy of the proposed method.It was found that the results of La, Nd, Eu, Gd, Er and Yb obrained using proposed method showed concordance with certified values with RSD of 1.1%-5.2%.