Analysis of organic residues of archaeological origin by high-temperature gas chromatography and gas chromatography-mass spectrometry

Organic residues are extracted from materials of archaeological interest by solvent extraction and subjected directly to high-temperature gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The use of high-temperature GC allows intact acyl lipids, e.g., triacylglycerols, diacylglycerols, monoacylglycerols and wax esters, to be analysed without prior degradation (e.g., saponification) to release constituent fatty acids and alcohols. Trimethylsilylation is employed to block protic sites in free fatty acids and hydroxylated components. The data obtained from temperature programmed GC and GC-MS analyses, employing immobilised apolar (dimethyl polysiloxane type) stationary phases, provide essential compositional information that would be lost if the more conventional degradative approach to acyl lipid analysis was adopted.