Total Uncertainty of Radiocarbon Measurements of Marine Dissolved Organic Carbon and Methodological Recommendations

Content Provider	Semantic Scholar
Author	Druffel, Ellen R. M. Griffin, Sheila Mb Walker, Brett D. Coppola, Alysha I. Glynn, Danielle S.
Copyright Year	2013
Abstract	We report results of duplicate measurements of dissolved organic carbon concentrations ([DOC] as μM) and 14C in seawater in order to assess the total uncertainty of reported [DOC] and 14C measurements via the UV oxidation method. In addition, pure International Atomic Energy Agency standards analyzed over a 4-yr period are evaluated. We find the total uncertainty of 14C measurements to be ±4.0‰. However, in samples that were thawed, subsampled, and refrozen prior to UV oxidation, the total uncertainty of 14C measurements is on the order of ±10‰. The [DOC] measurements of these samples were also higher by 1.8 ± 0.3 μM. The reason(s) for these documented increases in total [DOC] and 14C uncertainty are unclear. In order to minimize any effects on sample measurements, we recommend the following: 1) regular monitoring of duplicate samples, DOC standards, and diluent (Milli-QTM) water for 14C and [DOC] measurements; 2) thawing a sample immediately and only once prior to UV oxidation; 3) avoid the use of DOC-leachable plumbing (such as PVC pipe) in both water systems feeding and within Milli-Q systems; and 4) consider the use of DOC-free diluents (i.e. pre-UV oxidized Milli-Q or sample water).
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Language	English
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Content Type	Text
Resource Type	Article