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L. Puchinger, R. Paltram, J. Schrattenecker, S. Feichtinger, J. Schaub:
"Organic Residue Analyses by GC/MS and HPLC/CAD shed Light on Human Chief Means of Subsistence in Ancient Times - Case Studies about Potsherds coming from Ephesos (Turkey) and Punta di Zambrone (South Italy)";
Talk: ChemCh 2014, Third International Congress on Chemistry for Cultural Heritage, Academy of Fine Arts, Vienna - Austria; 07-01-2014 - 07-05-2014; in: "ChemCh 2014, Third International Congress on Chemistry for Cultural Heritage, Book of Abstracts", (2014), 134 - 135.

Information about the organic subject matter of archaeological pottery can be used to gain further insight in the life-style of prehistoric or ancient cultures.
To identify the organic content in old finds usually is much more time-consuming and of course remarkable expensive compared to the inorganic analysis of historical objects. And even worse the various organic substances can have suffered of degradation over the centuries at a different degree so that the organic material excavated after millennia is an absolute new mixture of constituents.
Another problem is the differential take up of the major food groups by the pottery pores [1]. In food terms this means that the fats and oils which are primarily composed of small molecules from triglycerides, hydrocarbons and esters will be preferentially trapped in the matrix while proteins and carbohydrates are less likely to be accumulated, more especially in fine grained fabrics.
Organic residues of archaeological pottery are able to survive in three principal forms: as actual content preserved in situ as vessel fill, as visible layer on the interior or exterior of the pot or sherd and as adsorbed matter stored within the vessel wall. Chemical investigations of old jars and their fragments have revealed a wide range of compound types like vegetable oils, terrestrial and marine animal fats, resins, birch bark tar, plant waxes, beeswax, carbohydrates, proteins and so on [2]. Fortunately it is the non-polar lipid fraction that is well-preserved as the carbohydrates and proteins are particularly vulnerable to bacterial attack and other forms of decomposition processes.
A new double-stage chromatographic chemical-analytical approach tailored to the particular needs of pottery was developed to identify residues from the three main food classes: lipids, carbohydrates and proteins.
The first step is a relatively speedy pre-selection method for sample series carried out by pyrolysis gas chromatography/mass spectrometry (Py-GC/MS) to find out those sherds containing organic substances and being best-suited for the rather time-consuming second step which gives some more detailed results [3]. The ceramic powder has to be collected by scraping the material from the open pores of a new breakage with a dissecting tool. Pyrolysis products like long-chain alcohols and alkanes are characteristic for fat and oils while the presence of dibenzofurans may indicate carbohydrates, of nitriles proteins.

For the next and final step a new extraction scheme could be worked out allowing to analyze all three main classes from a single weighed portion of the sample. One part of the chloroform phase was silylated with N,O-bis(trimethylsilyl)-trifluoroacetamide + trimethylchlorosilane (BSTFA + TMCS) before having tested it for mono-, di-, triglycerides and sterols by GC/MS. The other chloroform part was hydrolyzed followed by derivatization with boron trifluoride (BF3) and GC/MS determination [4,5]. A mild hydrolysis had to be done with the sodium hydroxide phase additionally adding a hydrochloric-acid solution and an ion exchange resin. The amino acids were retarded on the exchanger and could be identified with an ultra high performance liquid chromatograph/charged aerosol detector (UHPLC/CAD). The carbohydrates remained in solution and were determined by the same chromatographic technique.
The practicality of this new double-stage method will be discussed on the basis of two large sets of potsherds stemming from the following sites:
The neolithic excavation place Çukuriçi Höyük near to the turkish town of Selcuk and the ruins of Ephesus, a favorite international and local tourist attraction (head of excavation Barbara Horejs).
The Italian Bronze Age excavation place Punta di Zambrone in South Calabria (head of excavation Reinhard Jung).

[1] J. Evans, G. Recchia: "Pottery function - trapped residues in bronze age pottery from Coppa Nevigata (Southern Italy)". Scienze Dell´ Antichita, 2001-2003 (2005), p. 187-201
[2] R.P. Evershed: "Organic residue analysis in archaeology - the archaeological biomarker revolution". Archaeometry 50, 6 (2008), p. 895-924
[3] L. Puchinger, F. Sauter, A. Gössl: "Identification of purple by means of pyrolysis gas chromatography/mass dpectrometry". In: "Conservation Science for the Cultural Heritage - Applications of Instrumental Analysis, Lecture Notes in Chemistry 79", issued by: Evangelia Varella; Springer-Verlag Berlin Heidelberg 2013, ISBN: 978-3-642-30984-7, p. 230-240
[4] F. Sauter, L. Puchinger, A. Graf, D. Thumm: "Studies in organic archaeometry II - analysis of the ancient content of a flask excavated in Troia". ARKIVOC, 2, 2001, p. 21-25
[5] F. Sauter, L. Puchinger, U. Schoop: "Studies in organic archaeometry VI - Fat analysis sheds light on everyday life in prehistoric Anatolia: traces of lipids identified in calcolithic potsherds excavated near Bogzkale, Central Turkey". ARKIVOC, Volume 2003, Part (XV): designated for General Papers, p. 15-21

Potsherds, Py GC/MS, GC/MS, lipids