Analytical pyrolysis with in-situ silylation, Py(HMDS)-GC/MS, for the chemical characterization of archaeological and historical amber objects

Abstract

Introduction: An optimised analytical technique based on pyrolysis coupled with gas chromatography/mass spectrometry (Py-GC/MS) and derivatisation in situ with hexamethyldisilazane (HMDS) was used to study several archaeological and artistic amber objects. The aim was to verify the authenticity of the objects and to provide historical information regarding the geographical origin of the ambers, and thus reveal the trade routes between different ancient civilizations. Results: Py-GC/MS using HMDS as a silylating agent enabled us not only to identify the geographical origin of the archaeological and artistic ambers as succinites, but also highlighted the degradation of amber objects revealing a lower abundance of free diterpenes on the surface. Conclusion: This work demonstrates the capability of Py-GC/MS with silylation in situ to identify the geographical origin of archaeological ambers and to provide crucial information regarding their degradation process. The porous and rough appearance of the outer layer can be correlated with the higher lixiviation and to the evaporation of free diterpenes from the surface. The knowledge of the amber degradation mechanisms is crucial to select proper conservation-restoration methods.

Evidence for Birch Bark Tar Use as an Adhesive and Decorative Element in Early Iron Age Central Italy: Technological and Socio‐Economic Implications

“…Baltic amber (succinite) becomes the by far more common variety of amber in southern Europe (Colombini et al . ), and reaches the Terramare area (Po plain) and the fringes of the Tosco‐Emilian Apennines in the Middle/Late Bronze Age (c. 1600–1150 bc ) following the ‘central route’ (de Navarro ; de Marinis ; Miari ; Bellintani ). The main amber route will then shift eastwards during the Final Bronze Age (c. 1150–900 bc ), when amber is still found in the Padanian region at Bismantova (de Marinis ; Bellintani ).…”

The surface degradation of Baltic amber: The depth‐profiling analysis and its application to historical object

“…Previous archeometric studies of amber have employed FTIR and diffuse reflectance infrared Fourier transform (DRIFT), [ 9 ] pyrolysis coupled with gas chromatography/mass spectrometry (Py‐GC/MS), [ 10 ] and solid‐state 13 C nuclear magnetic resonance (NMR) spectroscopy. [ 11 ]…”

Recent Advances in Analytical Pyrolysis to Investigate Organic Materials in Heritage Science

“…The chromatographic profile comprising lupane‐type triterpenoids and the pyrolysis products of polymerised suberin and suberan (aliphatic acids, alkanes and alkenes) led to the identification of birch bark tar in the formulation of archaeological adhesives from a wooden spindle recovered in a Gallo–Roman burial (3rd century AD) and from the golden sheath of a Thracian dagger (8th–7th centuries BC) recovered in Bulgaria. Pyrolysis has also been used in the molecular characterisation of fossil resins, entailing the identification of succinite, also known as Baltic amber, which travelled to Italy through the Amber route already during the 7th century BC.…”