RARE-EARTH ELEMENTS IN HYDROTHERMAL FLUIDS AND PLUME PARTICULATES BY INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY

This paper describes the measurement of the rare earth elements (REE) in fluids from deep-sea hydrothermal vents and in the particles that f orm as these fluids mix with sea water. The REE are extracted from flu ids by coprecipitation with hydrated iron (III). The REE are isolated from other elements on miniature cation exchange columns before being measured by inductively coupled plasma mass spectrometry (ICP-MS). Col umn separations overcome the problem of sensitivity depression caused by high dissolved solids at the orifice of the mass spectrometer and m inimize isobaric interferences from barium. Inter-laboratory calibrati ons with isotope-dilution thermal ionization mass spectrometry (IDTIMS ) demonstrate that the ICP-MS results are accurate at the 6% (2sigma) level.