Supercritical Fluids for Higher Extraction Yields of Lipids from Archeological Ceramics

The extraction and study of organic residues from ceramics has been a subject of interest for the last 50 years in archeology and archeological science. Lipids are among the best-preserved organic substances in archeological contexts and can provide information about the diets of ancient populations as well as past environments. Here, we present a method which demonstrates significantly improved extraction of lipids from archeological pots by replacing liquid organic solvents with supercritical fluids. Optimization of the procedure using response surface methodology (RSM) approach showed that, on our system, optimal conditions for supercritical extraction of lipids from synthetic fired clay ceramics could be achieved using carbon dioxide with 16 vol % of cosolvent EtOH–H2O (95:5 v/v) in 90 min at a flow rate of 2.3 mL/min, for a pressure of 30 MPa and a temperature of 50 °C. For all reference and archeological samples included in this study, lipid yields obtained by supercritical fluid extraction under these optimal conditions were systematically higher than by conventional solvent extraction. This study also highlighted a variability of the ratio of unsaturated versus saturated fatty acids depending on the extraction method. This can have important implications in the identification of the residue(s). The increased extraction efficiency provided by supercritical fluids, as well as their minimally destructive nature, enable new and refined approaches to residue analysis and dating of archeological ceramics

Saving Bones: a direct comparison of FTIR-ATR, whole bone percent nitrogen, and NIR

89th Annual Meeting of the American-Association-of-Physical-Anthropologists (AAPA), Los Angeles, CA, APR 15-18, 202

Developing the use of supercritical fluids in archaeological sciences

International audienceWhile they have been used extensively in industry, supercritical fluids have not yet been fully explored in the field of archaeological sciences. There are only few documented applications which are mostly related to cleaning, drying, and conservation of delicate archaeological artefacts: actively eroding iron objects, silk textiles and paper from historical records have been cleaned and stabilised using supercritical CO2; supercritical fluids have also been used to dry waterlogged corks or other wooden materials; a further two publications have focused on the use of supercritical fluids prior to radiocarbon dating.Here, I will briefly review these applications and present the results of two recent pilot studies. We successfully optimised a procedure using supercritical fluids to extract lipids from a broad range of archaeological ceramic fragments without having to powder them [1]. We also successfully removed conservation materials and soil contaminants from archaeological bones prior to radiocarbon dating using supercritical fluids [2]. Results obtained on both sets of samples show that supercritical fluids can provide a more efficient and greener alternative to liquid solvents for the non-destructive extraction of organic materials from archaeological artefacts and contribute significantly to a range of research questions in archaeological sciences.[1] Devièse T, Van Ham-Meert A, Hare V, Lundy J, Hommel P, Ivanovich Bazaliiskii V and Orton J (2018). "Supercritical fluids for higher extraction yields of lipids from archaeological ceramics." Analytical Chemistry 90(4): 2420–2424.[2] Devièse T, Ribechini E, Querci D and Higham T (2019). "Assessing the efficiency of supercritical fluid extraction for the decontamination of archaeological bones prior to radiocarbon dating." Analyst 144: 6128-6135

Developing the use of supercritical fluids in archaeological sciences

International audienceWhile they have been used extensively in industry, supercritical fluids have not yet been fully explored in the field of archaeological sciences. There are only few documented applications which are mostly related to cleaning, drying, and conservation of delicate archaeological artefacts: actively eroding iron objects, silk textiles and paper from historical records have been cleaned and stabilised using supercritical CO2; supercritical fluids have also been used to dry waterlogged corks or other wooden materials; a further two publications have focused on the use of supercritical fluids prior to radiocarbon dating.Here, I will briefly review these applications and present the results of two recent pilot studies. We successfully optimised a procedure using supercritical fluids to extract lipids from a broad range of archaeological ceramic fragments without having to powder them [1]. We also successfully removed conservation materials and soil contaminants from archaeological bones prior to radiocarbon dating using supercritical fluids [2]. Results obtained on both sets of samples show that supercritical fluids can provide a more efficient and greener alternative to liquid solvents for the non-destructive extraction of organic materials from archaeological artefacts and contribute significantly to a range of research questions in archaeological sciences.[1] Devièse T, Van Ham-Meert A, Hare V, Lundy J, Hommel P, Ivanovich Bazaliiskii V and Orton J (2018). "Supercritical fluids for higher extraction yields of lipids from archaeological ceramics." Analytical Chemistry 90(4): 2420–2424.[2] Devièse T, Ribechini E, Querci D and Higham T (2019). "Assessing the efficiency of supercritical fluid extraction for the decontamination of archaeological bones prior to radiocarbon dating." Analyst 144: 6128-6135

ELUCIDATING FUNERAL RITUALS IN BURIALS FROM THE END OF THE ROMAN EMPIRE: DEVELOPMENT OF A MULTI-ANALYTICAL APPROACH

This thesis presents the development and the principal results of a multi analytical approach dedicated to the characterisation of organic and inorganic materials recovered from three archaeological burials. The principal aim of this research was the identification of the preserved materials to understand their function in these funeral structures. The archaeological materials studied come from the catacomb of Saints Peter and Marcellinus in Rome where numerous bodies were simultaneously pilled up together and from two French sites located in Anché and Naintré where the bodies were contained in lead coffins. All sites, originating in the Roman Empire, are dated to the second-third century AD. The experimental part of the thesis was organised into three parts. First, the samples were observed and classified on the basis of their morphological features. Then, their analysis by FTIR spectroscopy allowed to obtain a first chemical identification. Finally, on the basis of the results obtained by FTIR spectroscopy, separative, structural and other spectroscopic techniques were implemented to enlarge knowledge relative to the nature and the state of degradation of each material. This multi-analytical protocol, optimised for the study of minute samples, allowed to identify a large range of materials such as resinous substances, dyes, minerals and textiles and provided new information, at a molecular level, about the processes of degradation of these materials in archaeological context. The association of archaeological data with chemical information allowed to understand the function of most of the materials present into the tombs. It demonstrated the use of clay and precious imported resins to embalm the bodies. The presence of gypsum and calcite established that all bodies were packed, an unusual funeral practice at this time. The same analytical protocol applied to anthropological materials, such as bones and skin fragments, shed new light on the diagenesis of human remains in their archaeological environment. From an historical point of view, this research revealed new elements about the rich funeral practices of the Roman Empire and increases knowledge about the technical know-how of the period, such as textile manufacture and purple dyeing. Moreover, new information about the exchanges of precious materials such as Baltic amber, frankincense and oriental textiles at this time was obtained

Adaptation(s) alimentaire(s) face aux instabilités climatiques au Pléistocène supérieur: Présentation Flash

International audienc

The ‘Treu Head’: a case study in Roman sculptural polychromy

International audienc

Adaptation(s) alimentaire(s) face aux instabilités climatiques au Pléistocène supérieur: Présentation Flash

International audienc

La datation des ossements archéologiques au CEREGE

International audienc

Scientific analysis of a preserved head of hair at Romsey Abbey, UK

International audienc