Galili Nir, Somlyay Anna, Aquila Giorgia, Wijker Reto, Gautschi Philip, Wacker Lukas, Hemingway Jordon D
Geological Institute, Department of Earth Sciences, ETH Zurich, 8092 Zurich, Switzerland.
Laboratory of Ion Beam Physics, Department of Physics, ETH Zurich, 8093 Zurich, Switzerland.
Anal Chem. 2025 Apr 8;97(13):7002-7009. doi: 10.1021/acs.analchem.4c04676. Epub 2025 Mar 28.
We introduce a novel high-precision method for oxygen-isotope analysis of iron (oxyhydr)oxides using high-temperature conversion isotope ratio mass spectrometry (HTC-IRMS). In this approach, a finely ground mixture of iron (oxyhydr)oxide and graphite is heated at 1450 °C in a helium flow environment, converting oxygen to CO gas with nearly 100% yield. Continuous-flow IRMS analysis of the liberated CO yields a precision of ±0.15‰ (1σ, = 28) and shows excellent agreement with (and improved precision over) traditional fluorination methods. This practical and safe technique expands access to oxygen-isotope measurements of iron oxides, thereby enhancing their utility in Earth and environmental sciences.
我们介绍了一种使用高温转换同位素比率质谱法（HTC-IRMS）对铁的（氢）氧化物进行氧同位素分析的新型高精度方法。在这种方法中，将细磨的铁（氢）氧化物与石墨的混合物在氦气流环境中于1450°C加热，使氧以近100%的产率转化为CO气体。对释放出的CO进行连续流IRMS分析，其精度为±0.15‰（1σ， = 28），并且与传统氟化方法相比显示出极佳的一致性（且精度有所提高）。这种实用且安全的技术拓宽了铁氧化物氧同位素测量的途径，从而提高了它们在地球和环境科学中的实用性。
