title: Separation of rare earth elements by anion-exchange chromatography using ethylenediaminetetraacetic acid as mobile phase.
abstract: Rare earth elements (REEs) form anionic complexes which can be separated isocratically by anion-exchange chromatography using ethylenediaminetetraacetic acid (EDTA) as the mobile phase. For easy detection and identification, inductively coupled plasma (ICP) MS was used as detection method. From pH 3.5 to 7.5, retention increases from La to Sm and then decreases again up to Lu. Above pH 8.5, the retention of the light lanthanides increased drastically. It seems that the stoichiometry and the charge of the REE-EDTA complexes change with the elution pH. This strange elution behaviour can be easily tuned for particular applications by selecting the elution pH. For example, at pH values between 5.5 and 7.5 most isobaric and polyatomic interferences which occur in ICP-MS detection of the lanthanides are eliminated. A mechanism for the stepwise formation of the REE-EDTA complexes as a function of pH is proposed.
authors.affiliation: Department of Physical and Analytical Chemistry, University of Oviedo, C/ Julián Clavería 8, 33006 Oviedo, Spain.
authors.forename: Ruben García
authors.initials: RG
authors.lastname: Fernández
authors.forename: J Ignacio
authors.initials: JI
authors.lastname: García Alonso
mesh_terms: D000837:Anion Exchange Resins; D002852:Chromatography, Ion Exchange / Q000379:methods*; D004492:Edetic Acid / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008674:Metals, Rare Earth / Q000302:isolation & purification*
chemical_list: D000837:Anion Exchange Resins; D008674:Metals, Rare Earth; D004492:Edetic Acid