Precision and mass fractionation in 14C analysis with AMS

Borg, Klaas van der; Alderliesten, C.; Jong, A.F.M. de; Brink, A. van den; Haas, Arthur; Kersemaekers, H.J.H.; Raaymakers, J.E.M.J.

doi:10.1016/s0168-583x(96)00713-6

Cited by 41 publications

(14 citation statements)

References 7 publications

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“…We observe the expected increase of the backgrounds with decreasing sample size, which is reproducible for the 6 batches. This effect is also observed by others and it is due to modern contamination [2,4,12]. We also observe that the 13 C/ 12 C ratio increases with decreasing sample size.…”

Section: Measurement Resultssupporting

confidence: 87%

Porous iron pellets for AMS 14C analysis of small samples down to ultra-microscale size (10–25μgC)

Rooij

Plicht

Meijer

2010

Nuclear Instruments and Methods in Physics Research Section B:

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a b s t r a c tWe developed the use of a porous iron pellet as a catalyst for AMS 14 C analysis of small samples down to ultra-microscale size (10-25 lgC). It resulted in increased and more stable beam currents through our HVEE 4130 14 C AMS system, which depend smoothly on the sample size. We find that both the expected decrease of oxalic acid standards and increase of backgrounds with decreasing sample size, due to increasing influence of contamination, are reproducible. Using a mass-dependent background correction for dead (1.0 ± 0.4 lgC) and modern (0.25 ± 0.10 lgC) contamination, we obtain reliable results for small samples down to 10 lgC and possibly smaller. Due to our low graphitization yield for ultra-small samples (increases from 40% to 80% on average with sample size), we measured graphite standards as small as 3 lgC. The standard deviation of the corrected activity is about 5% for a 10-lgC HOxII standard.Here we report the iron pellet technique, which is new to the best of our knowledge. It is generally applicable for AMS 14 C laboratories that want to measure small samples down to ultra-microscale size. As an illustrative test-case, we analyze 14 C data for IAEA-C5, C7 and C8 samples with masses ranging from 15 to 300 lgC.

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Section: Measurement Resultssupporting

confidence: 87%

Porous iron pellets for AMS 14C analysis of small samples down to ultra-microscale size (10–25μgC)

Rooij

Plicht

Meijer

2010

Nuclear Instruments and Methods in Physics Research Section B:

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“…Assuming 43 ± 13 at.g −1 , being the half of the asymptotic in-situ production, originates from the accumulation region we find for the 52-m core R = 0.45, taking into account a 30% extraction efficiency for the in situ components. That would mean a retainment of 23% in-situ 14 C of the firn in the ice, which is different from the observation by van der Kemp et al (2000) who do not observe in situ production in accumulating ice. …”

Section: Discussioncontrasting

confidence: 82%

“…A 95% efficiency is obtained in this on line oxidation procedure using platinum wire at 300 °C. The collected CO 2 fractions are converted into graphite and prepared for 14 C measurement with AMS (van der Borg et al 1987Borg et al , 1997. The contamination in the total extraction procedure has been determined from blanks and admixtures of CO and CO 2 of known activity and has been found to be 1.5 ± 0.5 pMC.…”

Section: Methodsmentioning

confidence: 99%

In-Situ Radiocarbon Production by Neutrons and Muons in an Antarctic Blue Ice Field at Scharffenbergbotnen: A Status Report

et al. 2001

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ABSTRACT. In the radiocarbon accelerator mass spectrometry ( 14 C AMS) analysis of gases obtained in a dry extraction from a 52-m Antarctic ice core, we observed 14 CO 2 and 14 CO concentrations decreasing with depth. The concentrations are explained in terms of in-situ production by neutrons and captured muons in ablating ice. The ratio of the 14 CO 2 concentration to that of 14 CO has been found to be constant at 1.9 ± 0.3. The ablation rates obtained of 42 ± 18 cm.yr −1 and 40 ± 13 cm.yr −1 for the neutron and muon components, respectively, are about three times higher than observed from stake readings. The discrepancy may point to an incomplete extraction of the dry extraction method. Using the constant ratio in 14 CO 2 and 14 CO concentrations we correct for the in-situ component in the trapped 14 CO 2 and deduce an age of 10,300 ± 900 BP for the ice core.

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“…by van der Borg et al (1997), who observed 13C and 14C depletion in the graphite produced when making small samples. The isotopic depletion was more pronounced the smaller the sample, but van der Borg et al do not attempt to correlate these results with the percentage yield of graphite from original CO 2 .…”

Section: Isotopic Fractionation Effects During Incomplete Graphitizationmentioning

confidence: 96%

Biogeochemical applications of compound-specific radiocarbon analysis

Pearson¹

1999

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Compound-specific carbon isotopic (013C and !J.14C) data are reported for lipid biomarkers isolated from Santa Monica Basin (SMB) and Santa Barbara Basin (SBB) surface sediments. These organic compounds represent phytoplanktonic, zooplanktonic, bacterial, archaeal, terrestrial, and fossil carbon sources. The lipids include long-chain n-alkanes, fatty acids (as FAMEs), n-alcohols, C 30 mid-chain ketols and diols, sterols, hopanols, and ether-linked C4o-biphytanes of Archaea.The data show that the carbon source for most of the biomarkers is marine euphotic zone primary production or subsequent heterotrophic consumption of this biomass. Two lipid classes represent exceptions to this finding. !J.14C values for the n-alkanes are consistent with mixed fossil and contemporary terrestrial plant sources.The archaeal isoprenoid data reflect chemoautotrophic growth below the euphotic zone.The biomarker class most clearly representing marine phytoplanktonic production is the sterols. It is suggested, therefore, that the sterols could serve as paleoceanographic tracers for surface-water DIC.The isotopic data are used to construct two algebraic models. The first calculates the contributions of fossil and modem vascular plant carbon to 5MB n-alkanes. This model indicates that the !J.14C of the modern component is +235%0 (post-bomb) or 0%0 (pre-bomb). The second model uses these values to determine the origin of sedimentary TOe. The results are comparable to estimates based on other approaches and suggest that -60% of 5MB TOC is of marine origin, modern terrestrial and fossil sources contribute -10% each, and the remaining -20% is of unknown origin.iii For all of our mothers.iv ACKNOWLEDGEMENTS

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Precision and mass fractionation in 14C analysis with AMS

Cited by 41 publications

References 7 publications

Porous iron pellets for AMS 14C analysis of small samples down to ultra-microscale size (10–25μgC)

Porous iron pellets for AMS 14C analysis of small samples down to ultra-microscale size (10–25μgC)

In-Situ Radiocarbon Production by Neutrons and Muons in an Antarctic Blue Ice Field at Scharffenbergbotnen: A Status Report

Biogeochemical applications of compound-specific radiocarbon analysis

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