Stable Isotope Analysis (δ13C, δ15N and δ18O) of Killer Whale Dentine: Evaluating Treatment Methods and Establishing Best Practices

IF 1.8 3区化学 Q4 BIOCHEMICAL RESEARCH METHODS

Rapid Communications in Mass Spectrometry Pub Date : 2026-09-15 DOI:10.1002/rcm.70176

Maeva Terrapon, Philip S. Hammond, Rona A. R. McGill, Jason Newton, Julie Dougans, Cory J. D. Matthews, Sascha K. Hooker

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引用次数: 0

Abstract

Rationale

Stable isotope measurements in odontocete teeth can be used to reconstruct lifetime ecology, but some pre-treatments may introduce bias. Isolating dentine collagen with HCl decalcification, removing the organic matrix or drying dentine prior to the analysis of structural carbonates can introduce unintended variability, limiting comparability among studies and populations. This study tested pre-treatment methods to quantify their effects.

Methods

Killer whale teeth were sectioned, annual growth layers microdrilled, and powder allocated to treatments. For collagen δ¹³C and δ¹⁵N, 75 samples were analysed via EA-IRMS as untreated bulk dentine and after 0.25 N HCl decalcification. For structural carbonate δ¹³C and δ¹⁸O, treatment with 30% H₂O₂ was compared with plasma-ashing and with no treatment (n = 16); and we examined the removal of residual water by comparing samples oven-dried at 80°C or 100°C with untreated samples (n = 10). All samples for carbonate analysis were injected with 104% orthophosphoric acid to generate CO₂, which was analysed using continuous-flow IRMS.

Results

HCl decalcification caused mass loss (96.6% ± 2.0%) but yielded collagen of an acceptable quality (C:N = 3.3 ± 0.2). Compared with untreated dentine, collagen δ¹³C decreased (Δmedian = −0.34‰) while δ¹⁵N did not differ significantly. Organic-matrix removal treatments altered both isotopes: plasma-ashed samples showed large negative shifts compared with untreated samples in δ¹³C (Δmedian = −9.04‰) and δ¹⁸O (Δmean = −13.48‰) and reduced measurable carbon. H₂O₂ treatments lowered δ¹³C relative to untreated samples (Δmean = −0.93‰) but showed no consistent δ¹⁸O effect. Drying at 80°C minimised δ¹³C and δ¹⁸O variability.

Conclusions

HCl decalcification is recommended before δ¹³C and δ¹⁵N collagen analysis of killer whale dentine, or a δ¹³C correction factor (here −0.34‰) should be applied. Treatments were unsuitable when undertaking structural carbonate analyses of hydroxyapatite: we suggest that untreated powder oven-dried overnight at 80°C should be used, and we emphasise the importance of pre-treatment tests prior to any new study.

查看原文本刊更多论文

虎鲸牙本质的稳定同位素分析（δ13C、δ15N和δ18O）：评估治疗方法和建立最佳实践

理论基础稳定同位素测量可以用来重建牙尖牙的一生生态，但一些预处理可能会引入偏差。在分析结构碳酸盐之前，用盐酸脱钙分离牙本质胶原，去除有机基质或干燥牙本质可能会引入意想不到的变异性，限制了研究和人群之间的可比性。本研究测试了预处理方法，以量化其效果。方法对虎鲸牙齿进行切片，钻取年生长层，配粉处理。75个样品作为未处理的大块牙本质和0.25 N HCl脱钙后，通过EA-IRMS分析胶原δ13C和δ15N。对于构造碳酸盐δ13C和δ18O， 30% H2O2处理与等离子体灰化处理和未处理比较（n = 16）；我们通过比较在80°C或100°C下烘干的样品与未处理的样品（n = 10）来检查残余水的去除情况。所有用于碳酸盐分析的样品都被注入104%的正磷酸以产生二氧化碳，使用连续流IRMS进行分析。结果HCl脱钙导致组织丢失（96.6%±2.0%），但胶原质量可接受（C:N = 3.3±0.2）。与未处理的牙本质相比，胶原δ13C降低（Δmedian = - 0.34‰），δ15N差异不显著。有机基质去除处理改变了两种同位素：等离子体灰化样品的δ13C （Δmedian =−9.04‰）和δ18O （Δmean =−13.48‰）与未处理样品相比有较大的负移，可测碳减少。与未处理样品相比，H2O2处理降低了δ13C （Δmean = - 0.93‰），但δ18O的影响不一致。在80°C下干燥使δ13C和δ18O变化最小化。结论虎鲸牙本质δ13C和δ15N胶原分析前建议采用HCl脱钙，或采用δ13C校正系数（这里为- 0.34‰）。在对羟基磷灰石进行结构碳酸盐分析时，不适合进行处理：我们建议应使用未经处理的粉末，在80°C下过夜烘干，我们强调在任何新研究之前进行预处理测试的重要性。

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来源期刊

Rapid Communications in Mass Spectrometry 化学-分析化学

CiteScore

4.10

自引率

5.00%

发文量

219

审稿时长

2.6 months

期刊介绍： Rapid Communications in Mass Spectrometry is a journal whose aim is the rapid publication of original research results and ideas on all aspects of the science of gas-phase ions; it covers all the associated scientific disciplines. There is no formal limit on paper length ("rapid" is not synonymous with "brief"), but papers should be of a length that is commensurate with the importance and complexity of the results being reported. Contributions may be theoretical or practical in nature; they may deal with methods, techniques and applications, or with the interpretation of results; they may cover any area in science that depends directly on measurements made upon gaseous ions or that is associated with such measurements.