A set of laboratory methods for detecting, identifying and characterizing molecular or chemical traces preserved on artifacts, ecofacts or within sediments in order to infer former contents, materials, use or activities; methods include targeted and untargeted extraction, separation and instrumental identification (e.g., GC–MS, LC–MS, FTIR, stable isotopes).

Principle

Molecular and chemical compounds produced by organic or inorganic materials can persist in archaeological contexts long enough to record past use or contents, but the detectable signal is a filtered, altered record shaped by preservation, contamination, and sampling.

Demonstration

Illustrative scenario → A fragment of pottery from a hypothetical site is sampled: lipids are extracted, derivatized and analysed by GC–MS; the analyst detects specific fatty acid profiles and ω-(o-alkylphenyl) alkanoic acids consistent with heated animal fats; from recognition of these biomarkers the analyst infers repeated cooking of animal products, subject to considerations of contamination and context.

Misapplication

Concluding a single, specific activity (e.g., cooking of a named species) from a generic biomarker signal without accounting for post-depositional contamination, reuse, or overlapping sources; the semantic error is treating a probabilistic, taphonomically altered signal as definitive proof.

Consequence

Residue analysis can provide direct molecular evidence that complements typology and context, enabling inferences about vessel contents, diets or materials; but its evidential value is conditional and probabilistic, requiring chain-of-custody, appropriate controls and contextual integration.

Reversal

When preservation is poor (intense heat, oxidizing soils) or contamination overwhelming, residues may be absent or misleading; conversely, some inorganic residues (e.g., mineralized salts or pigments) may persist when organics do not, changing the expected signal.

Boundary

Applies to organic and some inorganic molecular traces preserved in porous matrices (ceramics, sediments, calculus, coatings). It does not apply to artifacts that cannot retain molecular residues (freshly manufactured metal implements without adhering deposits) nor does it by itself provide precise chronological assignment.

Semantic Tension

Specificity of identification (e.g., assigning a residue to a particular foodstuff) ↔ Preservation and taphonomic alteration that reduce resolution and increase ambiguity.

Synthesis

Residue analysis converts microscopic chemical evidence into constrained, probabilistic statements about past behaviour; its utility depends on laboratory rigor and contextual integration rather than on molecular detection alone.