Evidence map›Paper›PMID 38923072›Full record

ArticleRapid communications in mass spectrometry : RCM2024

Experimental assessment of elemental analyzer isotope ratio mass spectrometry normalization methodologies for environmental stable isotopes.

Sawyer Balint, Morgan Schwartz, Drew N Fowler, Stella Linnekogel, Sáde Cromratie Clemons, Laura K Burkemper

Abstract read
In one paragraph

Article in Rapid communications in mass spectrometry : RCM, 2024. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

6 authors.

Sawyer BalintORISE Participant, U.S. EPA Atlantic Coastal Environmental Sciences Division, Narragansett, Rhode Island, United States.ORCID https://orcid.org/0000-0003-1088-0358
Morgan SchwartzU.S. EPA Atlantic Coastal Environmental Sciences Division, Narragansett, Rhode Island, United States.ORCID https://orcid.org/0000-0002-0836-7320
Drew N FowlerLouisiana Cooperative Fish and Wildlife Research Unit, U.S. Geological Survey, Baton Rouge, Louisiana, United States.
Stella LinnekogelUK Centre for Ecology & Hydrology Lancaster, Lancaster, UK.
Sáde Cromratie ClemonsDepartment of Geography, University of Colorado Boulder, Boulder, Colorado, United States.
Laura K BurkemperCenter for Stable Isotopes, University of New Mexico, Albuquerque, New Mexico, United States.

Funding

Intramural EPA EPA999999Oak Ridge Institute for Science and EducationUS Environmental Protection Agency Office of Research and Development
6 · The paper itself

Abstract

rationaleIn stable isotope mass spectrometry, isotope delta values are normalized to internationally recognized reference scales using a combination of certified and in-house isotope reference materials. Numerous techniques exist for performing this normalization, but these methodologies need to be experimentally assessed to compare their effect on reproducibility of isotope results.

methodsWe tested normalization methods by the number of reference materials used, their matrix, their isotope range, and whether normalization required extrapolating beyond the isotope range. We analyzed eight commercially available isotope reference materials on a ThermoFinnigan Delta-V isotope ratio mass spectrometer (IRMS) and an Elementar VisION IRMS for nitrogen and carbon isotope composition via solid combustion with an elemental analyzer and computed every possible isotope normalization (n = 612). Additionally, we assessed how sample matrix affected linearity effects on both instruments using five in-house reference materials.

resultsNormalizations exhibited the best performance when the reference materials spanning an isotope range of at least 20‰ were matrix matched with the samples and did not require extrapolation beyond the calibration curve. When these conditions were not met, the number of reference materials used had a significant effect on accuracy, with normalizations composed of two reference materials exhibiting particularly inconsistent performance at isotope ranges below 20‰. Linearity effects were found to exceed instrument precision by two orders of magnitude irrespective of matrix type and were not predicted by working gas diagnostics.

conclusionsInterlaboratory comparability of isotope results is improved when operators of elemental analyzer isotope ratio mass spectrometry (EAIRMS) systems select reference materials spanning an isotope range of at least 20‰. Additionally, using three or more isotopic reference materials, avoiding extrapolation beyond the range of the normalization curve, and matching the matrix of the reference materials to the samples improve normalizations.

Identifiers

PMID38923072
PMCPMC11284645

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.