DETERMINATION OF RARE-EARTH ELEMENTS AND YTTRIUM IN 9 GEOCHEMICAL REFERENCE SAMPLES USING A NOVEL GROUP SEPARATION PROCEDURE INVOLVING MIXED-ACID ELUTION ION-EXCHANGE CHROMATOGRAPHY

Rare earth data for nine well-known geochemical reference samples were obtained using a rapid and efficient cation exchange chromatographic separation procedure. It involves the use of a mixed-acid eluent (HCl and HNO3) on a 15 x 1 cm column of Bio-Rad AG50-X8 (200-400 mesh) to remove matrix and many trace elements from rock solutions. The rare earth elements are removed from the column using 60 ml 7M HNO3. The pre-concentration procedure described is routinely used in this laboratory for the determination of the rare earth elements by mass spectrometry-isotope dilution, and has been satisfactorily used for their determination using inductively-coupled plasma-source atomic emission spectrometry.