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Methods

NOSAMS General Statement of 14C Procedures

Document describing general radiocarbon analysis procedures, calculations, and reporting conventions in place at NOSAMS.

 

Calculations and Reporting of Results

Description of how radiocarbon measurements are made and the corrections applied to produce final results.

 

Sample Preparation Protocols:

Organic Carbon (OC) Pretreatment:

Combustion of Organic Carbon Samples (OC)

Acidification for Inorganic Carbon Samples (carbonates)

Extraction of Dissolved Inorganic Carbon (DIC) by Water Stripping

Graphitization:

Contamination check sampling protocol (swipes)

Foil-wrapping loose organic carbon samples for submission (video)

 

Publications Describing Methods:

UV Oxidation for Dissolved Organic Carbon - Ultraviolet oxidation of DOC samples

Xu, L, Roberts, ML, Elder, KL, Kurz, MD, McNichol, AP, Reddy, CM, Ward, CP, Hanke, UM. 2021. Radiocarbon in Dissolved Organic Carbon by UV Oxidation: Procedures and Blank Characterization at NOSAMS. Radiocarbon, 63(1), 357-374. DOI: 10.1017/RDC.2020.102

Xu, L, Roberts, ML, Elder, KL, Gagnon, A, Kurz, MD. 2022. Radiocarbon in Dissolved Organic Carbon by UV Oxidation: An Update of Procedures and Blank Characterization at NOSAMS. Radiocarbon, 64(1), 195-199. DOI: 10.1017/RDC.2022.4

 

Extraction of Dissolved Inorganic Carbon (DIC)
REDICS - A membrane transfer technique removes dissolved inorganic carbon from an acidified water sample in the form of CO2.

Gospodinova, K, McNichol, AP, Gagnon, A, Walter, Shah, SR. 2016. Rapid extraction of dissolved inorganic carbon from seawater and groundwater samples for radiocarbon dating. Limnology and Oceanography – Methods 14:24-30, DOI: 10.1002/lom3.10066

Water Strip (WS) - Dissolved inorganic carbon is "stripped" in an automated system in our Sample Prep Lab using acidification and sparging with nitrogen to "strip" the evolving CO2 from the water.

McNichol, AP and Jones, GA, 1991 Measuring 14C in seawater ΣCO2 by accelerator mass spectrometry, WHP operations and methods. In Joyce, T., Corry, C. and Stalcup, M., eds. 1991 WOCE Operations Manual. Part 3.1.2, Requirements for WHP Data Reporting. Woods Hole, Massachusetts, WHPO Publication 90–1: 71 p.

McNichol, AP, Jones, GA, Hutton, DL, Gagnon, AR, Key, RM, 1994 The Rapid Preparation of Seawater Sigma-Co2 for Radiocarbon Analysis at the National Ocean Sciences AMS Facility. Radiocarbon 36(2):237-246, DOI: 10.1017/S0033822200040522

 

Graphitization Methods - reduction of CO2 to solid carbon on iron catalyst

Goehring B, Wilson J, Nichols K, A. 2019. A fully automated system for the extraction of in situ cosmogenic carbon-14 in the Tulane University cosmogenic nuclide laboratory. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. 455:284-292, ISSN: 0168-583X; DOI: 10.1016/j.nimb.2019.02.006

Vogel JS, Southon JR, Nelson DE, Brown TA, 1984. Performance of catalytically condensed carbon for use in accelerator mass spectrometry, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. 5(2):289-293, ISSN 0168-583X, DOI: 10.1016/0168-583X(84)90529-9

Pearson A, McNichol AP, Schneider RJ, von Reden KF. 1998. Microscale AMS 14C measurement at NOSAMS. Radiocarbon 40(1):61–75, DOI: 10.1017/S0033822200017902

Shah Walter, SR, Gagnon, AR, Roberts, ML, McNichol, AP, Gaylord, MC Lardie, Klein, E. 2015. Ultra-Small Graphitization Reactors for Ultra-Microscale C-14 Analysis at the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) Facility. Radiocarbon 57(1):109-122, DOI: 10.2458/azu_rc.57.18118

Elder, KL, Roberts, ML, Walther, T, Xu, L. 2019. Single step Production of graphite from organic Samples for Radiocarbon Measurements, Radiocarbon 61(6):1843-1854, DOI: 10.1017/RDC.2019.136

 

Data Reduction Methods

Roberts, ML, Elder, KL, McNichol, AP, Jenkins, WJ, Gagnon, AR, Xu, L, Hlavenka, JD, Longworth, BE. 2019. 14C Blank Corrections for 25–100 μg Samples at the National Ocean Sciences AMS Laboratory. Radiocarbon, 61(5), 1403-1411 DOI: 10.1017/RDC.2019.74.