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Fully resolved high-precision measurement of 36 S for sulfur reference materials
  • Jiayang Sun,
  • James Farquhar
Jiayang Sun
University of Maryland at College Park Department of Geology

Corresponding Author:[email protected]

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James Farquhar
University of Maryland at College Park Department of Geology
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Abstract

Advances in sulfur isotope measurement techniques have led to increased analytical precision. However, accurate measurement of 36S remains a challenge, hindering research such as that focused on microbial metabolic processes. This difficulty arises partly from isobaric interferences of 36SF 5 + at m/z = 131 amu, namely 186WF 4 2+ and 12C 3F 5 + which lead to scale compression. Our study develops an interference-free four-sulfur isotope measurement method using the high-resolution mass spectrometer Panorama. Panorama’s peak scan showed that the relative intensity of 186WF 4 2+ was initially 9.4% of 36SF 5 + but was reduced to 1.5% through tuning, while the 12C 3F 5 + relative intensity dropped from 74% to 40% after flushing with air and continued to decrease over time. Theoretically, an unresolved isobaric interference with 2% relative intensity could cause a 1‰ underestimation in a sample with a real δ 36S value of +60‰. We analyzed three IAEA sulfur isotope standards. Recommended 36S values we obtained relative to IAEA-S-1 are Δ 36S IAEA-S-2 = 1.238 ± 0.040‰, and Δ 36S IAEA-S-3 = -0.882 ± 0.030‰. For cases where the interferences cannot be removed, we offer a calibration method to correct for the scale compression effect. This involves bracketing two or more IAEA standards in the sample measurement sequence and then extending the measured IAEA δ 36S values by a calibration factor to match the values reported in this study. Applying this calibration factor to the samples effectively corrects the scale compression effect.
04 Nov 2023Submitted to Rapid Communications in Mass Spectrometry
04 Nov 2023Submission Checks Completed
04 Nov 2023Assigned to Editor
04 Nov 2023Review(s) Completed, Editorial Evaluation Pending
10 Nov 2023Reviewer(s) Assigned
04 Feb 20241st Revision Received
04 Feb 2024Submission Checks Completed
04 Feb 2024Assigned to Editor
04 Feb 2024Review(s) Completed, Editorial Evaluation Pending
18 Feb 2024Reviewer(s) Assigned
13 Mar 2024Editorial Decision: Revise Minor