Mass spectrometry reveals contents of ancient Greek vase

Skip to Navigation

News

  • Published: Jul 11, 2016
  • Author: Jon Evans
  • Source: Moscow Institute of Physics and Technology
  • Channels: Base Peak

Using mass spectrometry, Russian scientists have identified the components of the oldest bitumen sample to be found in an ancient vase and also made an accurate estimate of its age. In a paper in the Journal of Mass Spectrometry, the researchers from the Moscow Institute of Physics and Technology (MIPT) in Russia, together with various other research institutes, propose a new and more effective approach to analyzing organic compounds in ancient artefacts.

Bitumen is a form of petroleum found in natural deposits; its use dates back to the Stone Age. The Greeks used bitumen in construction, medicine and warfare – it is possible that the legendary 'Greek fire' was based on bitumen. Recently, Russian archaeologists discovered an ancient amphora filled with bitumen on the Taman Peninsula, a highly volcanically active region on the coast of the Black Sea (numerous petroleum seeps are located there) and a possible source of the bitumen imported by the Greeks.

The analysis of ancient bitumen samples can reveal their age and origin. This is because the bitumen is gradually broken down by bacteria over the years, leading to the oxidation of the organic molecules in the bitumen. As a result, older samples contain more oxygen atoms.

Elemental analysis of the Taman sample indicated an oxygen content of 11%, as opposed to 1% or less in fresh petroleum samples, with the other elements – carbon, hydrogen, nitrogen and sulfur – present in the normal amounts. This level of oxygen suggests that the bitumen in the amphora had been degrading for around 2500 years. However, the elemental analysis couldn’t reveal the identity of the molecules containing all this oxygen; to do this, the researchers turned to mass spectrometry.

Distinguishing the numerous peaks in the mass spectra of bitumen from one another is a challenge, and so the researchers utilized advanced ultrahigh-resolution mass spectrometry techniques developed at MIPT, allowing them to distinguish molecules whose masses differ by only a tiny amount. This meant that not one of the individual components in the bitumen sample – and there were tens of thousands of them – escaped their attention, and also allowed the researchers to determine the elemental composition of these components.

This analysis revealed that most of the oxygen-containing molecules in the Taman bitumen sample possess four to nine oxygen atoms. Samples of ordinary petroleum, however, contain numerous compounds with two oxygen atoms and very few with more than three or four oxygen atoms. To check that oxidation was responsible for this transformation, the researchers replicated the process in petroleum by exposing it to ozone. This produced molecules with an oxygen content similar to that of the bitumen from the amphora, supporting the theory that the Taman sample bears the effect of prolonged oxidation.

"Ultrahigh-resolution mass spectrometry is an immensely powerful technique in analytical chemistry," said Evgeny Nikolaev, scientific head of MIPT's Laboratory of Ion and Molecular Physics, and senior author of the paper. "Applied to petrochemistry, archaeology and medicine, it provides a valuable insight into the molecular composition of a substance. The analysis of ancient bitumen has already revealed much about the transformations that petroleum undergoes over the course of millennia. Thanks to mass spectrometry, we might be able to obtain new information about the goods traffic and trade routes in the ancient world."

Social Links

Share This Links

Bookmark and Share

Microsites

Suppliers Selection
Societies Selection

Banner Ad

Click here to see
all job opportunities

Most Viewed

Copyright Information

Interested in separation science? Visit our sister site separationsNOW.com

Copyright © 2017 John Wiley & Sons, Inc. All Rights Reserved