A review on the determination of isotope ratios of boron with mass spectrometry

Abstract

The present review discusses different mass spectrometric techniques-viz, thermal ionization mass spectrometry (TIMS), inductively coupled plasma mass spectrometry (ICPMS), and secondary ion mass spectrometry (SIMS)-used to determine B/ B isotope ratio, and concentration of boron required for various applications in earth sciences, marine geochemistry, nuclear technology, environmental, and agriculture sciences, etc. The details of the techniques-P-TIMS, which uses Cs BO , N-TIMS, which uses BO , and MC-ICPMS, which uses B ions for bulk analysis or B and B ions for in situ micro-analysis with SIMS-are highlighted. The capabilities, advantages, limitations, and problems in each mass spectrometric technique are summarized. The results of international interlaboratory comparison experiments conducted at different times are summarized. The certified isotopic reference materials available for boron are also listed. Recent developments in laser ablation (LA) ICPMS and QQQ-ICPMS for solids analysis and MS/MS analysis, respectively, are included. The different aspects of sample preparation and analytical chemistry of boron are summarized. Finally, the future requirements of boron isotope ratios for future applications are also given. Presently, MC-ICPMS provides the best precision and accuracy (0.2-0.4‰) on isotope ratio measurements, whereas N-TIMS holds the potential to analyze smallest amount of boron, but has the issue of bias (+2‰ to 4‰) which needs further investigations. © 2016 Wiley Periodicals, Inc. Mass Spec Rev 36:499-519, 2017.

Application of 1013 ohm Faraday cup current amplifiers for boron isotopic analyses by solution mode and laser ablation multicollector inductively coupled plasma mass spectrometry

“…The external precision of the 5 ng/g solutions was ca 0.12 ‰ for δ 11 B NIST951a values, with each measurement consuming ≤1 ng boron. This sample consumption is lower than previously required for MC-ICP-MS measurements, and competitive with negative mode TIMS, 19,47 17,45,47 The results from the δ 11 B analyses of foraminifera and calcite samples are plotted in Figure 5 The consistency of our results with published values and the high internal precision demonstrate that the present method can be applied to natural samples.…”

“…The external precision of the 5 ng/g solutions was ca 0.12 ‰ for δ 11 B NIST951a values, with each measurement consuming ≤1 ng boron. This sample consumption is lower than previously required for MC‐ICP‐MS measurements, and competitive with negative mode TIMS, while achieving better external precision. Previous measurements using the same MC‐ICP‐MS instrument, but with standard 10 11 Ω Faraday cup amplifiers, are reported in Misra et al; a sample amount at least 3 times greater was required to achieve comparable precision.…”

“…Samples and standards are measured under similar ICP conditions and are assumed to be affected by the same degree of mass bias when the solutions are matrix and concentration matched (sample standard bracketing (SSB) technique). The high sensitivity of negative ion mode TIMS allows measurements of less than 1 ng boron to be made, but the external reproducibility is generally poorer than for MC‐ICP‐MS …”

“…within the shell or fragments thereof an individual calcifier, whereas MC-ICP-MS and TIMS are bulk analytical techniques that require dissolution of a larger sample, and can typically achieve higher precision. Boron isotopic measurements are conventionally reported as a parts per thousand (‰) deviation of 11 sensitivity of negative ion mode TIMS allows measurements of less than 1 ng boron to be made, but the external reproducibility is generally poorer than for MC-ICP-MS. 19 Prior to the introduction of solutions into the ICP of the MC-ICP-MS instrument, the boron must be quantitatively separated from the sample matrix without inducing isotopic fractionation and without contamination from the laboratory environment, which is in itself challenging. Boron can be chemically separated from the matrix using resin columns 20,21 with elution in dilute nitric acid.…”

Fast and precise boron isotopic analysis of carbonates and seawater using Nu Plasma II multi‐collector inductively coupled plasma mass spectrometry and a simple sample introduction system

“…Boron isotope extraction and purification techniques have evolved considerably. 33,34 Chemical separation of B from carbonates and water samples is typically achieved using ion-exchange or a microsublimation technique 18,30 ; most common ion-exchange methods typically involve B-specific resin Amberlite IRA 743. 17,19,35 The application of Amberlite IRA 743 resin is based on its strong affinity for B at pH >5, which requires careful pH adjustment to ensure complete recovery.…”