@article {hanke_sequential_2023,
	title = {Sequential thermal analysis of complex organic mixtures: Procedural standards and improved CO2 purification capacity},
	journal = {Radiocarbon},
	volume = {65},
	number = {2},
	year = {2023},
	note = {Publisher: Cambridge University Press},
	month = {03/2023},
	pages = {389{\textendash}409},
	abstract = {Sequential thermal analysis allows for deconvoluting the refractory nature and complexity of carbon mixtures embedded in mineral matrices for subsequent offline stable carbon and radiocarbon (14C) isotope analyses. Originally developed to separate Holocene from more ancient sedimentary organic matter to improve dating of marine sediments, the Ramped Pyrolysis and Oxidation (RPO) apparatus, or informally, the {\textquotedblleft}dirt burner{\textquotedblright} is now used to address pressing questions in the broad field of biogeochemistry. The growing interest in the community now necessitates improved handling and procedures for routine analyses of difficult sample types. Here we report on advances in CO2 purification during sample processing, modifications to the instrumentation at the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) facility, and introduce sodium bicarbonate procedural standards with differing natural abundance 14C signatures for blank assessment. Measurements from different environmental samples are used to compare the procedure to the different generations of sequential thermal analyses. With this study, we aim to improve the standardization of the procedures and prepare this instrumentation for innovations in online stable carbon isotopes and direct AMS-interface measurements in the future.},
	keywords = {chemical analysis, dirt burner, full oxidation (FOX) mode, Radiocarbon dating, ramped pyrolysis oxidation},
	issn = {0033-8222, 1945-5755},
	doi = {10.1017/RDC.2023.13},
	url = {https://www.cambridge.org/core/journals/radiocarbon/article/sequential-thermal-analysis-of-complex-organic-mixtures-procedural-standards-and-improved-co2-purification-capacity/E225F01B421614EE176553014E7B38BE},
	author = {Hanke, Ulrich M. and Gagnon, Alan R. and Reddy, Christopher M. and Gaylord, Mary C. Lardie and Cruz, Anne J. and Galy, Valier and Hansman, Roberta L. and Kurz, Mark D.}
}
@article {longworth_radiocarbon_2022,
	title = {Radiocarbon measurement of CO2 from carbonate minerals using a hybrid gas ion source with an open split interface},
	journal = {Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms},
	volume = {531},
	year = {2022},
	month = {11/2022},
	pages = {49{\textendash}55},
	abstract = {We have developed a method for measuring radiocarbon in carbonate minerals as CO2 gas via a NEC MCSNICS hybrid sputter gas ion source (HGIS). The method uses helium as a carrier gas to displace CO2 from sample vials to an open split, where a glass capillary samples the mixture for delivery directly to the HGIS. This method skips the gas transfer and quantification steps used in a closed inlet HGIS system, simplifying sample measurement. Samples larger than 8 mg carbonate can be measured. Results from measurements of consensus standards (TIRI I, IAEA C2, and an internal modern shell standard), and samples from a marine core (F14C = 0.4{\textendash}1.15) show that the method agrees well with traditional AMS measurement of the same samples as graphite, and that the 1σ uncertainty is about 1\%. We discuss advantages and disadvantages of continuous flow sample introduction, and the effect of reduced precision on calibrated age-depth models produced using gas-source data.},
	keywords = {Carbonate, Hybrid gas ion source, radiocarbon},
	issn = {0168-583X},
	doi = {10.1016/j.nimb.2022.08.013},
	url = {https://www.sciencedirect.com/science/article/pii/S0168583X2200218X},
	author = {Longworth, Brett E. and Burton, Joshua R. and Pendleton, Simon L. and Moser, Sydney D. and Roberts, Mark L. and Kurz, Mark D.}
}
