A protocol for distilling animal body water from biological samples and measuring oxygen and hydrogen stable isotopes via cavity ring-down spectroscopy

• Published in: Isotopes in environmental and health studies Vol. 60; no. 3; pp. 229 - 250
• Main Authors: Steele, Zachary T., Caceres, Karen, Jameson, Austin D., Griego, Michael, Rogers, Elizabeth J., Whiteman, John P.
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis 03.05.2024; Taylor & Francis Ltd
• Subjects: Animal metabolism; animals; Biological properties; Biological samples; Body water; carbon; Carbon sources; Cavity ringdown; Cryogenic; doubly labeled water; Food chains; Food sources; Food webs; Habitat changes; habitats; Hydrogen; hydrogen-2; Instrumentation; isotope ecology; Isotopes; metabolic water; metabolism; nitrogen; Oxygen; Oxygen enrichment; oxygen-17 excess; oxygen-18; Picarro; plasma; Signal processing; Signal to noise ratio; Spectroscopy; Stable isotopes; Tracer techniques; triple oxygen isotopes; Water analysis; Cryogenic; triple oxygen isotopes; metabolic water; oxygen-18; doubly labeled water; Picarro; isotope ecology; hydrogen-2; plasma; oxygen-17 excess
• ISSN: 1025-6016; 1477-2639; 1477-2639
• DOI: 10.1080/10256016.2024.2323201

The application of stable isotope analysis (SIA) to the fields of ecology and animal biology has rapidly expanded over the past three decades, particularly with regards to water analysis. SIA now provides the opportunity to monitor migration patterns, examine food webs, and assess habitat changes in current and past study systems. While carbon and nitrogen SIA of biological samples have become common, analyses of oxygen or hydrogen are used more sparingly despite their promising utility for tracing water sources and animal metabolism. Common ecological applications of oxygen or hydrogen SIA require injecting enriched isotope tracers. As such, methods for processing and analyzing biological samples are tailored for enriched tracer techniques, which require lower precision than other techniques given the large signal-to-noise ratio of the data. However, instrumentation advancements are creating new opportunities to expand the applications of high-throughput oxygen and hydrogen SIA. To support these applications, we update methods to distill and measure water derived from biological samples with consistent precision equal to, or better than, ± 0.1 ‰ for δ 17 O, ± 0.3 ‰ for δ 18 O, ± 1 ‰ for δ 2 H, ± 2 ‰ for d-excess, and ± 15 per meg for Δ 17 O.