Exploration of anthropological specimens by GC‐MS and chemometrics

Abstract

Anthropological specimens combine a variety of unfavorable characteristics, rendering their evaluation an analytical challenge. Their remarkable status is primarily based on two characteristics: (i) these very rare samples of human origin are testimonies of human history and are, therefore, available only in minute amounts for analytical purposes, and (ii) the analysis of these samples is extremely limited by the decomposition of molecules, which are easily detected in living organisms, such as nucleic acids and proteins, but are subject to rapid post-mortem decay. In this article, we review the methods and results of archaeometry, emphasizing the role of MS combined with chemometrics. Focusing on experimental results for fatty acid profiles, specimens from mummies from different civilizations were compared. Considering in particular the Tyrolean Iceman, the application of chemometric methods to GC-MS data recovers essential information about the preservation and the storage conditions of mummies.

Solid‐phase extraction in combination with GC/MS for the quantification of free fatty acids in adipocere

“…As it is the change in FFA that is of interest in this study, to monitor the stage of adipocere formation, the relative percentage of FFA for each tissue and hence the noted change in composition from unsaturated fatty acids to saturated fatty acids is shown in Table 5. As shown, the FFA compositions of pig adipose tissue and pig adipocere show similar resolution to the standard mixture and broadly reflect those previously published [4,39]. The total ion chromatogram signal shown is the sum of absolute peak intensities m/z 73.…”

Probing dietary change of the Kwädąy Dän Ts'ìnchį individual, an ancient glacier body from British Columbia: I. Complementary use of marine lipid biomarker and carbon isotope signatures as novel indicators of a marine diet

“…No intact tri-, di-or mono-acylglycerols, which predominate in living tissue lipids, were detected. Rather, even-numbered, straight-chain saturated (C 12:0 FA , 0.8%; C 14:0 FA , 9.0%; C 16:0 FA , 29.4% and C 18:0 FA , 6.2%) and monounsaturated (C 18:1 FA , 6.0%, C 16:1 FA , 0.2%) FAs were detected in abundances consistent with degraded mammalian tissue (Bereuter et al, 1996;Makristathis et al, 2002;Varmuza et al, 2005). The appreciable abundance of C 14:0 FA compared to its low abundance in modern bone (ca.…”

“…Hydroxy acids are characteristic by-products of adipocere-like degradation processes observed in glacial deposits; most common are 10-hydroxyhexadecanoic acid and 10-hydroxyoctadecanoic acid, which are likely to derive from hydration of the double bonds of endogenous palmitoleic and oleic acids, respectively (Takatori, 1996;Takatori and Yamaoka, 1977a,b). Indeed, 10-hydroxyoctadecanoic acid represented the dominant lipid (27%) in the trabecular bone of Otzi, the Tyrolean Iceman (Varmuza et al, 2005). The detection of 12-hydroxy analogues of C 18 , C 20 and C 22 unsaturated FAs in addition to the 10-hydroxy derivatives is uncommon; a hydroxyl group at the C-12 position has only previously been reported in a 4000-year-old desiccated Nubian mummy (Gülac xar et al, 1990).…”

“…''Otzi'', the 5200-year-old Tyrolean Iceman) and more recent corpses deposited in Alpine glaciers and lakes (Bereuter et al, 1996;Varmuza et al, 2005). Molecular analysis of solvent-extractable components from adipocere, skin, muscle and bone samples of glacier corpses have revealed highly diagnostic lipid profiles consistent with degraded products of endogenous tissue fatty acids (FAs), typically being dominated by free FAs and hydroxy FAs (Varmuza et al, 2005).…”

“…''Otzi'', the 5200-year-old Tyrolean Iceman) and more recent corpses deposited in Alpine glaciers and lakes (Bereuter et al, 1996;Varmuza et al, 2005). Molecular analysis of solvent-extractable components from adipocere, skin, muscle and bone samples of glacier corpses have revealed highly diagnostic lipid profiles consistent with degraded products of endogenous tissue fatty acids (FAs), typically being dominated by free FAs and hydroxy FAs (Varmuza et al, 2005). Although not attempted previously, it was considered here that such fatty material might retain diagnostic dietary information, since the FA composition of human tissues is highly representative of the distribution of FAs in the diet Summers et al, 2000;Valero-Garrido et al, 1990).…”