Determination of radium isotope ratios and abundances in geologic samples by thermal ionization mass spectrometry.
We describe chemical separation and mass spectrometric procedures for the measurement of radium isotopes in geologic samples. These methods provide 226Ra/228Ra ratio measurements for 1 g or less of rock sample containing subpicogram amounts of radium with precision better than 1.5% (95% confidence level). Radium-226 concentrations were measured by isotope dilution for smaller sample sizes (100-500 mg) containing as little as 1-10 fg of total 226Ra with similar high precision.
Volpe
A M
AM
Isotope Geochemistry, Los Alamos National Laboratory, New Mexico 87545.
Olivares
J A
JA
Murrell
M T
MT
D005844:Geology / Q000379:methods; D007554:Isotopes; D013058:Mass Spectrometry / Q000379:methods; D011883:Radium / Q000032:analysis*
D007554:Isotopes; D011883:Radium