Supercritical Fluid Extraction (SFE) for the Removal of Lipid and Interfering Compounds Prior to Radiocarbon Dating of Archaeological Artifacts Using Teledyne Isco Syringe Pumps

Introduction The radiocarbon dating of many archaeological artifacts, such as Egyptian mummies, can be inaccurate due to contamination from soil organic matter. Traditional decontamination methods require the use of harsh acid-base pretreatment methods, which can be destructive to these delicate aged artifacts [1]. The supercritical fluid extraction (SFE) pretreatment using carbon dioxide with methanol as co-solvent has the potential to replace such methods and, when coupled with a non-destructive argon or oxygen plasma for microgram carbon removal, can serve as a method for sample preparation prior to accelerator mass spectrometry isotope ratio determinations [2]. In this study, a supercritical fluid extraction system consisting of two Teledyne Isco 100D pumps for pumping solvent (carbon dioxide) and modifier (methanol), and an Isco SFX-2-10 extraction module. Experimental extraction conditions of 3000 psi and 40°C using ultra high purity carbon dioxide were applied to fiber, macroflora, charcoal, and wood samples to reduce their lipid and soil humic content. Similar conditions were also used on burial gauzes from Egyptian mummies containing lipid constituents, and the gauzes were sent for plasma oxidation followed by radiocarbon dating.