Glossary

Acyl lipids Acyl lipids are the various components making up fat or oil. Pure fat or oil is made up largely of triacylglycerols - three fatty acids attached to a glycerol backbone. These compounds can break down so that each glycerol backbone contains only one or two fatty acids, in which case the newly produced compound is called a monoacylglycerol or a diacylglycerol, with fatty acids unattached to a glycerol called free fatty acids.

Absorbed residue Residual components from ancient activity (cooking, resource processing, etc.) which are absorbed within a porous archaeological matrix and able to survive chemical and microbial degradation during deposition.

Alkanols Alcohols with a long carbon chain that are found primarily in plant waxes.

Biomarker Components unique to a specific source or a class of sources: cholesterol is a biomarker for animal lipids, while theobromine is a biomarker for cacao, and various terpenoids are biomarkers for different families, genera, and species of trees.

Compound-specific isotope analysis A type of analysis that allows the separation of constituents in a residue by gas chromatography followed by the analysis of the carbon stable isotope ratio of each separate compound.

Derivatization A chemical reaction performed on the constituents of a residue to make it more amenable to chromatographic analysis.

Fatty acids Long carbon chain carboxylic acids that make up the major constituents of acyl lipids. Fatty acids are often stripped from the glycerol backbones during analysis and their relative abundance determined, to help interpret the origin of a residue.

Gas chromatography/mass spectrometry (GC/MS) A type of analysis in which a complex mixture of components are separated in the gas chromatograph, and each component is identified through mass spectrometry. organic residue analysis The analysis of any type of residue remaining attached to, or absorbed within, an archaeological artifact.

Unsaturation The presence of double bonds in an organic compound.

Visible residue Chemical components that are absorbed within the pores of a visible encrustation on an artifact, with a charred residue yielding the best chemical preservation.