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

Rationale: Boron isotope ratios (δ 11 B values) are used as a proxy for seawater paleo-pH, amongst several other applications. The analytical precision can be limited by the detection of low intensity ion beams from limited sample amounts. High-gain amplifiers offer improvements in signal/noise ratio and can be used to increase measurement precision and reduce sample amounts.Methods: 10 13 ohm amplifier technology has previously been applied to several radiogenic systems, but has thus far not been applied to non-traditional stable isotopes. Here we apply 10 13 ohm amplifier technology for the measurement of boron isotope ratios using solution mode MC-ICP-MS and laser ablation mode (LA-)MC-ICP-MS techniques. Precision is shown for referencematerials as well as for low-volume foraminifera samples. B from an in-house calcite standard was 1 ‰ (2SD) for individual spot analyses, and 0.3 ‰ for the mean of ≥10 replicate spot analyses. 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. ). The measurements were made within one session, running from high through to low concentrations. The accuracy and precision are maintained for solution concentrations as low as 5 ng/g allowing better than 0.2 ‰ precision (2σ) to be achieved for 1-ng runs LLOYD ET AL. Conclusions

Section: Application In Solution Mode Mc-icp-mssupporting

confidence: 78%

“…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.…”

Section: Resultsmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Lloyd

Sadekov

Misra

2017

“…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.…”

Section: Chemical Separationmentioning

confidence: 99%

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

Chen

Teng

Catling

2019

Rationale:The boron (B) isotopic composition in marine carbonates provides important insights into paleoclimate reconstruction and biomineralization. However, precise and accurate measurements of B isotopes using plasma-based mass spectrometry is difficult due to the volatile nature of B, which typically requires complex and more specialized sample introduction systems. Existing analytical protocols have mostly been based on Thermo Scientific Neptune Plus multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS) instruments, whereas methods based on Nu Plasma mass spectrometers are scarce. Methods:We have developed a simplified analytical protocol using Nu Plasma II MC-ICPMS with standard glass sample introduction systems. Boron extraction and purification were conducted using a two-stage column chemistry with cationexchange and Amberlite IRA 743 B-specific resin. A sample drying step was avoided, which allows for direct isotopic analysis after column chemistry. A wet plasma mode with a standard glass cyclonic spray chamber and a glass nebulizer was used instead of a more specialized perfluoroalkoxy (PFA) sample introduction system. Low residual B signals were achieved with a relatively short period of wash-out with 0.5 N HNO 3 . Results:The external precision is better than 0.30‰ (2SD) calculated from the longterm bracketing standard, NIST SRM 951a. The overall robustness of the method was demonstrated by measurements of the international carbonate standard JCp-1 (δ 11 B = +24.49 ± 0.36‰, 2SD) and seawater (δ 11 B = +39.98 ± 0.35‰), which are consistent with reported values. Conclusions:Our method provides an alternative approach for B isotope analysis using a routine wet plasma MC-ICPMS setup that can facilitate geochemical and environmental application of B isotopes.

Comparative study of B content and δ¹¹B in the enamel of isolated teeth from brothers in the same family

Miao

et al. 2021

RationaleThe quantity of boron (B) and its isotopic ratios in tooth can provide information on dietary habits and oral health of individuals. These metrics are gradually being used in stomatology, environmental science and geochemistry.MethodsThis study measured the B concentration and δ11B in the enamel of isolated teeth from brothers in the same family living in high‐B‐exposure areas at different times using inductively coupled plasma mass spectrometry (ICP‐MS) and multicollector ICP‐MS.ResultsThe results demonstrate that B content in tooth samples of two brothers is related to the time of shedding. The earlier the time of shedding, the lower is the B content in tooth. The B content increased from 20.5 μg/g of the central incisor (6–7 years old) of the younger brother to 50.4 μg/g of the second molar (10–12 years old). And B content for the elder brother increased from 28.7 to 58.3 μg/g at the same positions. In the same family, the diet and environmental input of B is basically similar, and the B exposure is basically the same every year. The annual growth rate of B for the younger brother in this experiment is about 4.98 μg/g per year and that for the elder brother is about 4.93 μg/g per year. The δ11B of shed teeth at different times from the same person is basically similar, but different from person to person. The δ11B of shed teeth from the elder brother varies from 15.5‰ to 17.9‰ and from the younger brother varies from 5.2‰ to 6.7‰. The δ11B is quite different for the brothers in the same family who had the same food and environmental intake of B.ConclusionsThe experimental data confirmed the relationship between the information of B (B content and δ11B) in shed teeth and B exposure. They provided an experimental basis using modern human teeth to apply B‐isotope paleo‐environmental significance.