Determination of stable isotope ratios of Ba by ¹³⁰Ba–¹³⁵Ba double-spike total evaporation method using thermal ionization mass spectrometry (DS-TEV-TIMS)

Abstract

An analytical method for determining the stable isotope ratios of Ba was developed by using thermal ionization mass spectrometry (TIMS) and the ¹³⁰Ba–¹³⁵Ba double-spike total evaporation method (DS-TEV). We determined the isotope ratios of the ¹³⁰Ba–¹³⁵Ba double spike to be ¹³⁴Ba/¹³⁰Ba = 0.076623, ¹³⁵Ba/¹³⁰Ba = 1.081975, and ¹³⁷Ba/¹³⁰Ba = 0.209356 by using the intercept values of the mass-dependent fractionation lines and mixing line.

The measured repeatability of δ^137/134Ba of the National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) 3104a was ±0.018‰ (2SD: 2 standard deviations, n = 7) based on the double-spike total evaporation method using thermal ionization mass spectrometry (DS-TEV-TIMS). The repeatability is comparable to or better than the best repeatability of Ba isotope ratios ever reported.