Kautenburger Ralf, Beck Horst Philipp
Institute of Inorganic and Analytical Chemistry and Radiochemistry, Saarland University, D-66041 Saarbrücken, Germany.
J Chromatogr A. 2007 Aug 3;1159(1-2):75-80. doi: 10.1016/j.chroma.2007.03.092. Epub 2007 Mar 30.
For the long-term storage of radioactive waste, detailed information about geo-chemical behavior of radioactive and toxic metal ions under environmental conditions is necessary. Humic acid (HA) can play an important role in the immobilisation or mobilisation of metal ions due to complexation and colloid formation. Therefore, we investigate the complexation behavior of HA and its influence on the migration or retardation of selected lanthanides (europium and gadolinium as homologues of the actinides americium and curium). Two independent speciation techniques, ultrafiltration and capillary electrophoresis coupled with inductively coupled plasma mass spectrometry (CE-ICP-MS) have been compared for the study of Eu and Gd interaction with (purified Aldrich) HA. The degree of complexation of Eu and Gd in 25 mg l(-1) Aldrich HA solutions was determined with a broad range of metal loading (Eu and Gd total concentration between 10(-6) and 10(-4) mol l(-1)), ionic strength of 10 mM (NaClO4) and different pH-values. From the CE-ICP-MS electropherograms, additional information on the charge of the Eu species was obtained by the use of 1-bromopropane as neutral marker. To detect HA in the ICP-MS and separate between HA complexed and non complexed metal ions in the CE-ICP-MS, we have halogenated the HA with iodine as ICP-MS marker.
对于放射性废物的长期储存，了解放射性和有毒金属离子在环境条件下的地球化学行为的详细信息是必要的。腐殖酸（HA）由于络合作用和胶体形成，在金属离子的固定或迁移中可以发挥重要作用。因此，我们研究了HA的络合行为及其对所选镧系元素（铕和钆作为锕系元素镅和锔的同系物）迁移或阻滞的影响。为了研究铕和钆与（纯化的Aldrich）HA的相互作用，比较了两种独立的形态分析技术，即超滤和毛细管电泳与电感耦合等离子体质谱联用（CE-ICP-MS）。在25 mg l(-1)的Aldrich HA溶液中，在广泛的金属负载量（铕和钆的总浓度在10(-6)至10(-4) mol l(-1)之间）、10 mM（NaClO4）的离子强度和不同的pH值条件下，测定了铕和钆的络合程度。从CE-ICP-MS电泳图中，通过使用1-溴丙烷作为中性标记物，获得了关于铕物种电荷的额外信息。为了在ICP-MS中检测HA，并在CE-ICP-MS中分离HA络合的和未络合的金属离子，我们用碘作为ICP-MS标记物对HA进行了卤化。
