Work

Comparing Dual Water Equilibration Methods for Hydrogen Stable Isotope Analysis of Plant Carbohydrates and Proteinaceous Animal Samples

Year: 2025

Type: article

Abstract: RATIONALE: H) of organic samples carries information about processes including hydrology, climate, ecology, and plant metabolism. Numerous methods exist to control for hydrogen in organic samples that can isotopically exchange with ambient water or vapor. METHODS: We compared two established dual water steam equilibration approaches to control for exchangeable hydrogen in isotopic analysis: hot vacuum equilibration using the Uniprep autosampler and hot atmospheric pressure equilibration under varying equilibration temperatures and times. We evaluated how the extent of hydrogen isotope exchange and calculated exchange-corrected hydrogen stable isotope values varied among methods and sample types. RESULTS: H values that agreed better with values from chemical derivatization, while Uniprep values agreed better with values provided for purchased reference materials based on room temperature equilibrations. Best long-term precision was achieved with fitted rather than prescribed isotope fractionation factors for equilibration. CONCLUSIONS: Different equilibration methods can give reproducible yet distinct results. This is due to varying degrees to which different methods access non-carbon-bound hydrogen that is difficult to liberate from interior hydrogen bonds in complex biological structures such as cellulose or keratins. The optimal method depends on the application.

Source: Rapid Communications in Mass Spectrometry

DOI: 10.1002/rcm.10091

Authors: Daniel B. Nelson, Ansgar Kahmen, Jochem Baan, Selina Hugger, Cristina Mercoli, Meisha Holloway‐Phillips

Institution: University of Basel

Language: English

Topic: Isotope Analysis in Ecology

Subfield: Ecology

Field: Environmental Science

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,840

Funder: European Research Council