Rapid and high-precision determination of boron isotope ratios in boron carbide by thermal ionisation mass spectrometric measurement of the dicaesium metaborate cation

Abstract

The boron isotope ratio has been determined in boron carbide by using a recently developed high-precision thermal ionisation mass spectrometric technique based on the measurement of Cs₂BO₂⁺. Boron carbide is usually decomposed by use of a fusion procedure. The use of Cs₂CO₃ as a flux has been investigated. Direct fusion of samples on the filament has been compared with samples fused in platinum crucibles prior to loading. The direct fusion procedure has the advantage of being fast and simple, without sacrificing precision. The ¹⁰B/¹¹B ratios yielded were slightly lower (0.05%) than those of conventional fusion procedures. Precisions of better than 0.03% were achieved with use of both fusion procedures.