Quantitative assessment of polyatomic interferences for the measurement of uranium and plutonium isotope ratios at ultra-trace level using MC-ICP-MS

Tomita, Jumpei; Tomita, Ryohei; Suzuki, Daisuke; Yasuda, Kenichiro; Miyamoto, Yutaka

no journal, , 

Formation of polyatomic interferences made of an atom of heavy element and atoms in plasma such as argon and oxygen is known to create problems for their measurements using ICP-MS. In this study, quantitative assessment of polyatomic interferences for the measurement of U and Pu isotope ratios at ultra-trace level using MC-ICP-MS was conducted. For U isotopes, significant polyatomic interferences caused by IrAr, PtAr and PtAr were observed at the mass of 233, 234 and 236, respectively. When 1 ppb of natural uranium solution (IRMM184) containing 0.4 ppb of Pt was measured, U/U isotope ratio was roughly estimated to be two-fold higher than certified value due to the interference. For Pu isotopes, small interference from Pb (PbAr) was observed at the mass of 244 while other obvious interferences were not found.