Towards online ramped oxidation (ORO)-AMS for thermal dissection and serial radiocarbon analysis of complex organic matter

By constraining organic carbon (OC) turnover times and ages, radiocarbon ( 14 C) analysis has become a crucial tool to study the global carbon cycle. However, commonly used “bulk” measurements yield average turnover times, masking age variability within complex OC mixtures. One method to unravel intra-sample age distributions is ramped oxidation, in which OC is oxidized with the aid of oxygen at increasing temperatures. The resulting CO 2 is collected over prescribed temperature ranges (thermal fractions) and analyzed for 14 C content by accelerator mass spectrometry (AMS). However, all ramped oxidation instruments developed to date are operated in an “offline” configuration and require several manual preparation steps, hindering sample throughput and reproducibility. Here we describe a compact, online ramped oxidation (ORO) setup, where CO 2 fractions are directly collected and transferred for 14 C content measurement using an AMS equipped with a gas ion source. Our setup comprises two modules: (i) an ORO unit containing two sequential furnaces, the first of which holds the sample and is ramped from room temperature to ∼900°C, the second of which is maintained at 900°C and holds catalysts (copper oxide and silver) to ensure complete oxidation of evolved products to CO 2 ; and (ii) a dual-trap interface (DTI) collection unit containing two parallel molecular sieve traps, which alternately collect CO 2 from a given fraction and handle its direct injection into the AMS. Initial results for well-characterized samples indicate that 14 C content uncertainties and blank background values are like those obtained during routine gas measurements at ETH, demonstrating the utility of the ORO-DTI setup

Accelerator mass spectrometry · Organic matter · Radiocarbon dating · Chemistry · Hydrocarbon exploration and reservoir analysis · Image Processing and 3D Reconstruction · Isotope Analysis in Ecology · Geology · Paleontology

• Ramped oxidation and fine scale serial 14 C analyses of saltmarsh soils

  Open Access•Alex Houston, M H Garnett et al.•Radiocarbon•2026

  Incluir item

• Age Determinations by Radiocarbon Content

  Open Access•J R Arnold, W F Libby•Science•1949

  Incluir item

• Radiocarbon Dating of Soil Organic Matter

  Open Access•Yang Wang, Ronald Amundson et al.•Quaternary Research•1996

  Incluir item

• Micadas

  Open Access•Hans‐arno Synal, Hans-Arno Synal et al.•Nuclear Instruments and Methods…•2007

  Incluir item

• Sediment chronology in Antarctic deglacial sediments

  Open Access•C Subt, Kimberly A Fangman et al.•The Holocene•2015

  Incluir item

• Lea—a Novel Low Energy Accelerator for 14 C Dating

  Open Access•Urs Ramsperger, Daniele De Maria et al.•Radiocarbon•2024

  Incluir item

• Young, Old, and Weathered Carbon-Part 1

  Open Access•Evelyn M Keaveney, Paula J Reimer et al.•Radiocarbon•2015

  Incluir item

• Assessing the Blank Carbon Contribution, Isotope Mass Balance, and Kinetic Isotope Fractionation of the Ramped Pyrolysis/Oxidation Instrument at Nosams

  Open Access•Jordon D Hemingway, Valier V Galy et al.•Radiocarbon•2017

  Incluir item

• Influence of Different Acid Treatments on the Radiocarbon Content Spectrum of Sedimentary Organic Matter Determined by RPO/Accelerator Mass Spectrometry

  Open Access•Rui Bao, Ann P McNichol et al.•Radiocarbon•2019

  Incluir item

• Advancing Antarctic Sediment Chronology Through Combined Ramped Pyrolysis Oxidation and Pyrolysis-Gc-MS

  Open Access•Catherine E Ginnane, Jocelyn C Turnbull et al.•Radiocarbon•2024

  Incluir item

• A New Ramped Pyroxidation/Combustion Facility at 14 Chrono, Belfast

  Open Access•Evelyn M Keaveney, Gerard T Barrett et al.•Radiocarbon•2021

  Incluir item

• Sequential Thermal Analysis of Complex Organic Mixtures

  Open Access•Ulrich M Hanke, Alan R Gagnon et al.•Radiocarbon•2023

  Incluir item

• Discussion Reporting of 14 C Data

  Open Access•Minze Stuiver, Henry A Polach•Radiocarbon•1977

  Incluir item

• Complexity of Soil Organic Matter

  Open Access•Janet Rethemeyer, Christiane Kramer et al.•Radiocarbon•2004

  Incluir item