Programmes > Par auteur > Cohen-Ofri Ilit

Mass spectrometry, usually in combination with gas or liquid chromatography, has been used to aid in the identification of food and beverage residues extracted from ceramic artifacts for several decades. It has also been applied to the identification of hafting adhesives on stone tools. However, it has not been developed for the systematic analysis of micro-residues on stone tools. Yet, developing a method of residue analysis applicable to large sample sizes is essential for the field to move beyond anecdotal evidence for stone tool functions, to the point where it can provide data for rigorous testing of hypotheses regarding human tool use behavior.

In this paper we explore the application of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) as a technique which, due to its high sensitivity coupled with relative ease of sample preparation, has the potential to be developed into a method which could be applied on a large scale. We develop a method requiring minimal sample preparation, and show that MALDI-TOF-MS can detect the presence of large (up to 60 kDa), intact molecules on experimental stone tools coated with blood and muscle proteins. However, even light washing of the tools dramatically reduces the signal detected by the mass spectrometer. The implications of this result are two-fold: first, it means that artifacts that have been washed are unlikely to contain identifiable residues. Second, as amount of residue diminishes, contaminants and signal noise become more prominent, complicating interpretation of the mass spectra. These results provide a baseline for future development of the method.