Low- and high-molecular weight fractions of geological ambers detected by evolved gas analysis-mass spectrometry

We used evolved gas analysis-mass spectrometry (EGA-MS) to characterize a pool of ambers belonging to different geological varieties, with the aim of obtaining information on both their non-polymeric and polymeric components. Small molecular components can be trapped in amber during the fossilization process. Their characterization can provide insights into the maturation process of amber and help in determining its age and botanical origin. Most of the analyzed ambers showed two gas evolution regions, corresponding to the desorption of low-molecular weight compounds at low temperature, and to the pyrolysis of the macromolecular matrix at high temperature. We established characteristic m/z signals of the non-polymeric and polymeric fractions, and we were able to classify most of the samples in agreement with the available literature. We also performed principal component analysis of diterpenoid ambers using their average mass spectra. This allowed us to differentiate between succinite and rumanite ambers, which showed very similar spectra. The results demon-strate that EGA-MS constitutes a reliable technique to obtain information on the molecular composition of ambers, and on their relative content of low-and high-molecular weight fractions.