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 D_w’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，旨在为从天然样品的伴生基体元素中分离高电荷/离子半径比痕量元素提供更优异的应用潜力。以商用且经现场验证的TRU-和RE-Spec材料（Eichrom Technologies）为基础，我们制备并表征了三款在CMPO-TBP混合体系中TBP占比更低、甚至仅使用纯CMPO的树脂；通过测定约50种元素在不同浓度硝酸（HNO₃）与盐酸（HCl）介质中的分配比完成了相关表征。这些树脂还针对地球化学样品的分析应用场景开展了进一步性能评估。研究结果显示，地球化学、宇宙化学与环境科学领域的诸多目标元素（镧系元素、天然锕系元素、高场强元素）的重量分配比得到显著提升。结合优异的色谱性能，这些高重量分配比（D_w）可通过采用小型色谱柱并以较高的重力驱动流速运行，实现出色的基团分离。此外，为进一步提升对Fe(III)和Ti(IV)的选择性，我们还针对另一组浸渍了CMPO取代杯芳烃的树脂原型开展了初步研究。尽管获得了颇具前景的分配比数据，但这类原型无法制备出色谱性能达标的色谱柱，该方法仍有待开发更优的多孔惰性载体浸渍工艺。