Plasma oxidation has been pioneered by Marvin Rowe (Texas A&M University), Karen Steelman (University of Central Arkansas) and colleagues to extract organic carbon from mineral carbonate-contaminated rock art paints for radiocarbon dating. Recently, they have proposed the method also be used to extract carbon from archaeological artifacts that cannot tolerate traditional sampling methods. In this technique, the organic sample is exposed to an RF-generated plasma of excited oxygen species in which organic carbon is readily oxidized. Crucially, the sample temperature remains low (approximately 100 °C), allowing selective oxidation of organic carbon while leaving carbonate or oxalate mineral carbon in place. We have recently constructed a plasma oxidation apparatus based on Rowe's design and are beginning to investigate this technique. Our initial objectives are to investigate the rates and products of plasma oxidation of various materials, compare plasma oxidation sample preparation to more typical sample treatments for radiocarbon dating, such as acid-base-acid pretreatment and step heating, and to replicate some of Rowe et al.'s findings. Potential future applications for plasma oxidation in radiocarbon dating may involve exploiting the surface-active nature of the plasma oxidation reaction to investigate the 14C content of layered organic structures.
See more of Poster Session II
See more of The 10th International Conference on Accelerator Mass Spectrometry (September 5-10, 2005)