USING GC-MS AND HPLC-MS APPROACHES TO EVALUATE LIPIDS IN ARCHAEOLOGICAL CONTEXT

The present research project is based on the development of analytical methodologies for the investigation of the lipid content in archaeological finds. Ateration processes such as thermal decomposition, oxidation and hydrolysis of lipids can provide key elements to better interpret the origin of animal fats and vegetable oils partially or totally altered over the time [1]. For these purposes, triolein, trilinolein and tristearin standards as well as extra virgin olive oil (EVOO), particularly used in ancient Mediterranean societies, were subjected to in-lab thermo-oxidative treatments in order to simulate the natural degradation of lipid matter occurring in archaeological pottery. Gas chromatography (GC) and high-performance liquid chromatography (HPLC) analytical tecniques coupled to mass spectrometry (MS) were used for the separation and identification of the degradation products. In detail, the degradation of intact lipids was monitored by using non-aqueous reversed phase HPLC coupled to APCI mass spectrometry.With respect to low-volatility compounds, medium- and short-chain fatty acids, and (α,ω)-dicarboxylic acids were initially converted into trimethylsilyl (TMS) derivatives by a sylilation process, and analysed by GC-MS. In such respect, the separation were performed by using an apolar capillary column, 30m x 0.25 mm ID x 0.25 μm df. In both chromatographic techniques, the peak assignment was carried out evaluating two different identification paramenters: mass spectral fragmentation patterns and linear retention index (LRIs). Such approach allowed the univocal identification of lipid compounds, avoiding mistaken identifications. In conclusion, the analytical methodologies here proposed can also be fundamental in archaeological context, in order to identify specific archaeological biomarkers and unveil crucial hints about the daily life of ancient societies. References: [1] A. Irto, G. Micalizzi, C. Bretti, V. Chiaia, L. Mondello, P. Cardiano. Molecules 2022, 27, 3451.