TIMS measurements of full range of natural Ca isotopes with internally consistent fractionation correction

Dèzes, Mariia Oleksiivna; Bouman, Claudia; Nägler, Thomas; Mezger, Klaus; Villa, Igor Maria (2015). TIMS measurements of full range of natural Ca isotopes with internally consistent fractionation correction. International journal of mass spectrometry, 387, pp. 60-68. Elsevier 10.1016/j.ijms.2015.07.012

[img] Text
Naumenko.pdf - Published Version
Restricted to registered users only
Available under License Publisher holds Copyright.

Download (1MB) | Request a copy

This study presents static measurements of the Ca isotopic composition of standard reference materials SRM 915 a/b on a Triton Plus™ thermal ionization mass spectrometer with a specially developed Faraday cup array allowing simultaneous measurement of 40Ca and 48Ca. The total amount of Ca in all analyses was kept < 1 µg. With this setup the measurement uncertainties were 0.06 ‰ for 40Ca/44Ca and 0.12 ‰ for 48Ca/40Ca. Measuring all isotopes simultaneously better allows to test the internal consistency of different Ca isotope abundances reported in the literature. The exponential law was observed to correct incompletely instrumental mass fractionation. An improved fractionation correction based on the exponential law is proposed. It changes the 40Ca/44Ca ratio of SRM 915a (corrected relative to 42Ca/44Ca = 0.31221; 48Ca/44Ca = 0.08871) from 47.1635 ± 0.0028 to 47.1649 ± 0.0047. The measurements of SRM 915b were performed with different analytical conditions (runs were prolonged till complete filament load depletion). Even if the 40Ca/44Ca ratio of SRM 915b, when corrected with the simple exponential law, appears different (47.1532 ± 0.0038) from that of SRM 915a, it becomes coincident (47.1613 ± 0.0028) when corrected with a second-order refinement. This supports the use of the improved exponential law to obtain internally consistent Ca isotope ratio for natural samples.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geological Sciences

UniBE Contributor:

Dèzes, Mariia Oleksiivna; Nägler, Thomas; Mezger, Klaus and Villa, Igor Maria

Subjects:

500 Science > 550 Earth sciences & geology

ISSN:

1387-3806

Publisher:

Elsevier

Funders:

[UNSPECIFIED] Schweizer Nationalfonds

Language:

English

Submitter:

Igor Maria Villa-Toscani

Date Deposited:

08 Feb 2016 10:55

Last Modified:

08 Feb 2016 10:55

Publisher DOI:

10.1016/j.ijms.2015.07.012

Web of Science ID:

WOS:000361925300010

Uncontrolled Keywords:

TIMS; Static measurement, Ca isotopes, SRM915, Mass fractionation correction, 40Ca/44Ca

BORIS DOI:

10.7892/boris.75175

URI:

https://boris.unibe.ch/id/eprint/75175

Actions (login required)

Edit item Edit item
Provide Feedback