Simultaneous determination of non-natural isotopic composition of Li and B employing Li2BO2+ by Thermal Ionisation Mass Spectrometry

• Simultaneous determination of isotopic composition of lithium and boron for samples other than natural composition of lithium and boron.
• Molecular ion beam method was employed for the judicious selection of monitor pairs required for obtaining 6Li/7Li and 10B/11B ratios simultaneously.
• Relative uncertainty magnification factors were calculated theoretically and compared with the% deviation of the experimentally obtained ratios from the true isotopic ratios of lithium and boron, in order to validate the method.

Simultaneous isotopic analysis of lithium and boron was carried by Thermal Ionisation Mass Spectrometry employing Li2BO2+ as monitoring ions. This molecular ion beam method (MIBM) requires judicious selection of monitor pairs for the accurate determination of the isotopic ratios. Relative Uncertainty Magnification Factors for Li and B were theoretically evaluated for the simultaneous determination of isotopic abundance ratios of Li and B using Li2BO2+. The combinations of two molecular ion pairs that can be used for the simultaneous determination of both Li and B when the isotopic abundances of Li or B are different from that of natural abundance were identified based on these theoretical evaluations. It is observed that the selection of the monitor pairs for the simultaneous determination of isotopic composition of lithium and boron is simple when the difference in the isotopic abundance between the atom percent of 6Li &10B is large. The outcome of the theoretical calculations was verified by using the mixtures of lithium and boron with an atom ratio of B/Li about 5 prepared by mixing Svec lithium (a natural isotopic standard of lithium) with the synthetic mixtures of B having 10B varying from 10% to 95%.

Figure optionsDownload high-quality image (139 K)Download as PowerPoint slideFor natural 6Li/7Li and varying atom percent of 10B; Li refers to RUMF for Li for the ith CTMPS; Bj refers to RUMF for B for jth CTMPS.