@article {2643,
	title = {Influence of Different Acid Treatments on the Radiocarbon Content Spectrum of Sedimentary Organic Matter Determined by RPO/Accelerator Mass SpectrometryABSTRACT},
	journal = {Radiocarbon},
	volume = {61},
	year = {2019},
	month = {Jan-04-2019},
	pages = {395 - 413},
	abstract = {In practice, obtaining radiocarbon (C-14) composition of organic matter (OM) in sediments requires first removing inorganic carbon (IC) by acid-treatment. Two common treatments are acid rinsing and fumigation. Resulting C-14 content obtained by different methods can differ, but underlying causes of these differences remain elusive. To assess the influence of different acid-treatments on C-14 content of sedimentary OM, we examine the variability in C-14 content for a range of marine and river sediments. By comparing results for unacidified and acidified sediments [HCl rinsing (Rinse(HCl)) and HCl fumigation (Fume(HCl))], we demonstrate that the two acid-treatments can affect C-14 content differentially. Our findings suggest that, for low-carbonate samples, Rinse(HCl) affects the Fm values due to loss of young labile organic carbon (OC). Fume(HCl) makes the Fm values for labile OC decrease, leaving the residual OC older. High-carbonate samples can lose relatively old organic components during Rinse(HCl), causing the Fm values of remaining OC to increase. Fume(HCl) can remove thermally labile, usually young, OC and reduce the Fm values. We suggest three factors should be taken into account when using acid to remove carbonate from sediments: IC abundance, proportions of labile and refractory OC, and environmental matrix.},
	issn = {0033-8222},
	doi = {10.1017/RDC.2018.125},
	url = {https://www.researchgate.net/publication/328913959_Influence_of_different_acid_treatments_on_the_radiocarbon_content_spectrum_of_sedimentary_organic_matter_determined_by_RPOAccelerator_Mass_Spectrometry},
	author = {Bao, Rui and McNichol, Ann P and Hemingway, Jordon D and Lardie Gaylord, Mary C and Eglinton, Timothy I}
}
@article {1093,
	title = {Assessing the Blank Carbon Contribution, Isotope Mass Balance, and Kinetic Isotope Fractionation of the Ramped Pyrolysis/Oxidation Instrument at NOSAMS},
	journal = {Radiocarbon},
	volume = {59223{\textendash}22493970409},
	year = {2017},
	month = {Jan-02-2017},
	pages = {179 - 193},
	abstract = {We estimate the blank carbon mass over the course of a typical Ramped PyrOx (RPO) analysis (150-1000 degrees C; 5 degrees C x min(-1)) to be (3.7 +/- 0.6) mu g C with an Fm value of 0.555 +/- 0.042 and a delta C-13 value of (-29.0 +/- 0.1)parts per thousand VPDB. Additionally, we provide equations for RPO Fm and delta C-13 blank corrections, including associated error propagation. By comparing RPO mass-weighted mean and independently measured bulk delta C-13 values for a compilation of environmental samples and standard reference materials (SRMs), we observe a small yet consistent delta C-13 depletion within the RPO instrument (mean-bulk: mu = -0.8 parts per thousand; +/- 1 sigma = 0.9 parts per thousand; n = 66). In contrast, because they are fractionation-corrected by definition, mass-weighted mean Fm values accurately match bulk measurements (mean-bulk: mu = 0.005; +/- 1 sigma = 0.014; n = 36). Lastly, we show there exists no significant intra-sample delta C-13 variability across carbonate SRM peaks, indicating minimal mass-dependent kinetic isotope fractionation during RPO analysis. These data are best explained by a difference in activation energy between C-13- and C-12-containing compounds ((13-12)Delta E) of 0.3-1.8 J x mol(-1), indicating that blank and mass-balance corrected RPO delta C-13 values accurately retain carbon source isotope signals to within 1-2 parts per thousand.},
	keywords = {Ramped PyrOx; blank assessment; kinetic fractionation},
	issn = {0033-8222},
	doi = {10.1017/RDC.2017.3},
	url = {https://www.cambridge.org/core/product/identifier/S0033822217000030/type/journal_article},
	author = {Hemingway, Jordon D and Galy, Valier V and Gagnon, Alan R and Grant, Katherine E and Rosengard, Sarah Z and Soulet, Guillaume and Zigah, Prosper K and McNichol, Ann P}
}
