An analytical scheme of radiochemical neutron activation for the sequential determination of ultra-trace rare earth elements
(REEs) and highly siderophile elements (HSEs) in geological and cosmochemical samples is presented. Using this procedure,
several selected elements of REEs and HSEs were successively determined for geological reference samples and olivine crystals
separated from pallasite meteorites. Based on the data for geological reference samples, it was concluded that the procedure
presented in this study could yield data usable for cosmochemical discussion of the genesis of pallasite meteorites.
A simple and effective radiochemical procedure for radiochemical neutron activation analysis (RNAA) of ultra-trace siderophile
elements (Ru, Re, Os and Ir) and rare earth elements (REEs) in rock and meteorite samples is presented. To design the procedure,
several separation schemes of siderophile elements were examined by using radioactive tracers. By applying the procedure to
rock and meteorite samples, we have determined Ru, Re, Os, Ir and REEs, and confirmed that our values were in agreement with
the literature values. Our detection limits for Ru, Re, Os, La, Sm and Eu are significantly low compared with those for ICP-MS.