Osmium isotopic compositions by vapor phase sample introduction using a multi-collector ICP-MS

Osmium isotopic compositions have been measured using a vapor phase sample introduction technique in which volatile OsO4 is sparged directly into a multi-collector ICP-MS for analysis. Replicate analyses of an in-house solution standard yield an average188Os/192Os value that is within 10 ppm of the accepted natural value when corrected for mass discrimination using189Os/192Os, with a reproducibility of ±0.5 permil (2 SE, □ = 9) for samples containing 10 ng of Os. The average187Os/192Os measured for this solution agrees with the value determined by negative thermal ionization mass spectrometry to