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Graphite oxidation chemistry is relevant for designing cleaning strategies for radiocarbon dating samples

Joorab Doozha, Amir, Poduska, Kristin M.
Analytical methods 2019 v.11 no.22 pp. 2880-2887
analytical methods, archaeology, charcoal, cleaning, graphene, humic substances, oxidation, pH, radiocarbon dating, sonication, water treatment
We demonstrate that mixtures of graphite and lab-oxidized graphenic carbon materials can be separated into three individual components (graphite, graphene/graphite oxide (GO) and oxidative debris (OD)) by a series of aqueous treatments. Our results show that a key part of this separation procedure involves a water treatment and sonication near neutral pH in order to separate GO from OD. We show that the relative proportions of OD and GO – independent of any humic substances – can affect the ability of oxidized graphite to be suspended in water, which can influence the efficiency of the separation procedures we describe. We compare and contrast our protocol with others that are widely used for cleaning archaeological charcoal prior to radiocarbon dating. Our protocol has potential applications for tailored cleaning procedures for graphenic carbon materials, including the possibility of separating GO from both OD and graphite, for radiocarbon dating purposes.