Lipid Residue Analysis of Archaeological Pottery: An Introductory Laboratory Experiment in Archaeological Chemistry

Abstract

In this research-based experiment, students are introduced to the interdisciplinary field of archaeological chemistry by extracting and analyzing lipid residues absorbed in pottery. Reproduction archaeological pottery sherds are prepared by soaking ceramic fragments in individual or combinations of vegetable oils. Students crush and extract the absorbed residues, transesterify the recovered lipids to fatty acid methyl esters, and analyze the product by GC or GC/MS. Recovered residues are characterized by analysis of the major fatty acid peaks, as identified using reference standards or mass spectral databases. An archaeological context that links the sherds to the Minoan civilization is provided to students and must be considered to correctly identify the absorbed residue(s). The laboratory has been used in a topical archaeological instrumentation course that has attracted second to fourth year students majoring in chemistry, biochemistry, and anthropology, and museum studies minors. Pedagogically, the laboratory introduces students to techniques currently used in the field of archaeological chemistry while reinforcing fundamental concepts in sample isolation and preparation, derivatization, gas chromatography, mass spectrometry, and multicomponent sample analysis.

Fatty Acids and Their Metal Salts: A Review of Their Infrared Spectra in Light of Their Presence in Cultural Heritage

“…Relatively fewer cases have been reported in wooden containers such as coffins [ 39 ] or metal alloys such as copper [ 9 , 40 ]. Most of the above cases have been studied through gas chromatography combined either with mass spectrometry (GC-MS) [ 18 , 20 , 28 , 33 , 34 , 38 , 41 , 42 , 43 ] or isotope ratio mass spectrometry (GC-IRMS) [ 30 , 36 , 37 , 38 , 41 ]. This technique allows for the accurate quantification of analytes.…”

Lipids in Archaeological Pottery: A Review on Their Sampling and Extraction Techniques

“…In these solid–liquid extraction techniques, widely utilized in foodomics and lipidomics research, lipid compounds are simultaneously extracted and isolated into a liquid layer. For example, Harper et al utilized 5 mL of a 2:1 v / v dichloromethane:methanol solution to extract lipids from pottery [ 102 ]. Evershed et al extracted lipids from powdered sherds (2 g) by using a chloroform:methanol (10 mL, 2:1 by volume) solvent mixture [ 103 ].…”

“…The most common one is the saponification reaction followed by methylation or silylation, which is a classical method for the preparation of fatty acid methyl esters (FAMEs) from acylglycerols [ 111 ]. For example, Harper et al performed the methylation of lipid residues by using sodium hydroxide (KOH) in a methanol solution (5 M) as basic catalyst [ 102 ]. The methylation reaction was carried out in an ultrasonic bath for 30 min.…”

Using Pop-Culture to Engage Students in the Classroom

“…In several articles, authors describe aspects of popular culture (pop-culture) to teach chemistry using resources that are part of everyday life to engage students more effectively. Chemistry classes have been supplemented with material from arts such as music − (including jazz and opera , ) and paintings − (including fashion art), history, − archeology, − or literature. − As examples, educators illustrated chemistry with a Shakespeare’s play while others found inspiration in detective cases where chemistry was used by the perpetrator of a crime or in their identification. , The chemical references from Ian Fleming’s James Bond series of novels were used to illustrate chemical reactions and substances (sedatives, rocket fuels, etc.). The Harry Potter novel series also offered an opportunity to reproduce wizardry experiments in a chemistry lab (e.g., with invisible and color-changing inks, colored flame in a jam-jar).…”