Microgram scale pyrolysis mass spectrometric and pyrolysis gas chromatographic characterisation of geological and archaeological amber and resin samples

This paper is a preliminary report on the potential of pyrolysis mass spectrometry (PYMS) and pyrolysis gas chromatography mass spectrometry (PYGCMS) to characterise ambers and resins on a microgram scale. Extremely small amounts of sample are applied to a desorption probe and analysed in the mass spectrometer as a solid material without further pretreatment. The solids are heated and the resulting evaporation and thermal dissociation products of the polymeric network are analysed. The small sample requirement is not only important for precious archaeological samples, but could also be significant for geological and botanical studies for example when a "transsect" study through a nodule with a weathering layer is desirable. The high resolving power on the molecular level with the techniques applied is evident from data on a variety of ambers (succinites) and resins analysed and from data on three archaeological samples. Pyrolysis Gas Chromatographic and temperature resolved Pyrolysis-Chemical Ionisation - Mass Spectrometric data on bead fragments from a First Iron Age grave, the Mycene treasure and the Akhziv grave finds show a larger variability in succinite composition than demonstrated untill now. A Baltic amber provenance for the Tyrins wheel bead fragment from Akhziv seems unlikely, although the material analysed is a succinite.