Characterization of a Set of Improved, CMPO-Based, Extraction Chromatographic Resins: Applications to the Separation of Elements Important for Geochemical and Environmental Studies

This article describes several extraction chromatographic materials aiming to offer improved potential for isolating trace elements with high charge/ionic radius ratio from accompanying matrix elements in natural samples. Starting with commercially available, field-proven, TRU- and RE-Spec materials (Eichrom Technologies), three resins containing less TBP in the CMPO-TBP mixtures, or even neat CMPO only, have been prepared and characterized through measurement of the distribution ratios of some fifty elements in HNO3 and HCl media of variable strength. These resins were further evaluated for analytical applications on geochemical samples. The results highlight a strong enhancement of weight distribution ratios of many elements of interest in geochemistry, cosmochemistry, and environmental sciences (Lanthanides, naturally occurring Actinides, High Field Strength Elements). Combined with good chromatographic characteristics, these high Dw’s make it possible to achieve excellent group separations by using very small columns operated at relatively high, gravity-driven flow rate. Moreover, in an attempt to further improve the selectivity against Fe(III) and Ti(IV), preliminary investigations were made on an additional pair of resin prototypes impregnated with a CMPO-substituted calixarene. Although promising distribution ratio data were obtained, these prototypes did not permit to prepare columns with satisfactory chromatographic characteristics, and this approach still waits for a better impregnation methodof the porous inert support.

本文介绍了多款萃取色谱材料，旨在提升从天然样品的共存基体元素中分离高电荷/离子半径比痕量元素的可行性。以市售且经现场验证的TRU-Spec与RE-Spec材料（Eichrom Technologies公司）为基础，我们制备了三款树脂：其CMPO-TBP混合体系中TBP占比更低，甚至有一款仅使用纯CMPO；并通过测定约50种元素在不同浓度硝酸（HNO₃）和盐酸（HCl）介质中的分配比，对这些树脂进行了表征。随后，我们针对地球化学样品的分析应用，对这些树脂展开了进一步评估。结果表明，地球化学、宇宙化学与环境科学领域诸多目标元素（镧系元素、天然锕系元素、高场强元素）的重量分配比得到了显著提升。结合优异的色谱性能，这些较高的重量分配比（Dw）使得我们能够使用尺寸极小的色谱柱，以相对较高的重力驱动流速实现出色的元素组分离。此外，为进一步提升对三价铁（Fe(III)）与四价钛（Ti(IV)）的选择性，我们针对另一对负载了CMPO取代杯芳烃的树脂原型展开了初步研究。尽管获得了颇具潜力的分配比数据，但这些原型树脂无法制备出色谱性能合格的色谱柱，该方法仍需优化多孔惰性载体的浸渍工艺。