PRECONCENTRATION AND PURIFICATION OF RARE-EARTH ELEMENTS IN NATURAL-WATERS USING SILICA-IMMOBILIZED 8-HYDROXYQUINOLINE AND A SUPPORTED ORGANOPHOSPHORUS EXTRACTANT

8-Hydroxyquinoline immobilized on silica gel (silica-8HQ) and RE-Spec, a supported organophosphorus extractant, were used to preconcentrate and purify rare earth elements (REEs) from natural waters prior to their determination by isotope-dilution inductively coupled plasma mass spectrometry (ID-ICPMS). Preconcentration onto silica-8HQ is applicable to a wide range of trace metals, making it suitable for multielement ID-ICPMS studies, The silica-8HQ, RE-Spec technique concentrates REEs from 1 L or less of water into 1 mL of salt-free 0.1% nitric acid. The technique is rapid and has high REE yields (>80%) and low REE blanks (<2-6 pg). In addition, Ba separation is high, allowing determination of La and Eu by ID-less than or equal to 1300 pg of Ba is present in the final concentrates of sample solutions initially containing >4 mu g of Ba.