Application of 10(13) ohm Faraday cup current amplifiers for boron isotopic analyses by solution mode and laser ablation multicollector inductively coupled plasma mass spectrometry

Lloyd, Nicholas S and Sadekov, Aleksey Yu and Misra, Sambuddha (2018) Application of 10(13) ohm Faraday cup current amplifiers for boron isotopic analyses by solution mode and laser ablation multicollector inductively coupled plasma mass spectrometry. In: RAPID COMMUNICATIONS IN MASS SPECTROMETRY, 32 (1). pp. 9-18.

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Abstract

RationaleBoron isotope ratios (B-11 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. Methods10(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 reference materials as well as for low-volume foraminifera samples. ResultsThe baseline uncertainty for a 0.1 pA B-10(+) ion beam is reduced to <0.1 for a typical measurement period. The external precision is better than 0.2 parts per thousand (2SD) for B-11 measurements for solution samples containing as little as 0.8 ng total boron. For in situ microanalyses with LA-MC-ICP-MS, the external precision of B-11/B-10 from an in-house calcite standard was 1 parts per thousand (2SD) for individual spot analyses, and 0.3 parts per thousand for the mean of 10 replicate spot analyses. Conclusions10(13) ohm amplifier technology is demonstrated to offer advantages for the determination of B-11 values by both MC-ICP-MS and LA-MC-ICP-MS for small samples of biogenic carbonates, such as foraminifera shells. 10(13) ohm amplifier technology will also be of benefit to other non-traditional stable isotope measurements.

Item Type:	Journal Article
Publication:	RAPID COMMUNICATIONS IN MASS SPECTROMETRY
Additional Information:	Copy right for this article belongs to the WILEY, 111 RIVER ST, HOBOKEN 07030-5774, NJ USA
Department/Centre:	Division of Mechanical Sciences > Centre for Earth Sciences
Date Deposited:	27 Dec 2017 10:26
Last Modified:	27 Dec 2017 10:26
URI:	http://eprints.iisc.ac.in/id/eprint/58537

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