Republished from MIPT

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Russian scientists have identified the components of the oldest bitumen sample to be found in an ancient vase and made an accurate estimate of its age. In their article in the Journal of Mass Spectrometry, the researchers from the Moscow Institute of Physics and Technology (MIPT), the Skolkovo Institute of Science and Technology (Skoltech), the Institute for the History of Material Culture, the Talrose Institute for Energy Problems of Chemical Physics, and the Emanuel Institute of Biochemical Physics of the Russian Academy of Sciences (IBCP RAS) propose a new and more effective approach to organic compound analysis and introduce specially designed software.

Bitumen is a form of petroleum found in natural deposits. Its use dates back to the Stone Age. The word ‘mummy’, for example, derives from the Persian ‘mūm’, or ‘bitumen’, because this substance was used in embalming. The Greeks used bitumen in construction, medicine, and warfare—it is possible that the legendary ‘Greek fire’ was based on bitumen. The oldest amphora filled with bitumen (5ᵗʰ century BCE) was discovered by Russian archaeologists on the Taman Peninsula, a highly volcanically active region (numerous petroleum seeps are located there) and a possible source of the bitumen imported by the Greeks.

More oxygen as time goes by

The analysis of ancient bitumen samples can reveal their age and origin. US researchers have used a mummy to demonstrate that ancient Egyptian bitumen did not come exclusively from the Dead Sea. If the age of the bitumen sample from the amphora is indeed close to 2,500 years, this implies a prolonged period of biodegradation due to the activity of bacteria, causing oxidation of the organic molecules in bitumen, i.e. the gradual introduction of additional oxygen into the sample. This means that older samples contain more oxygen atoms.

Elemental analysis of the Taman sample indicated an oxygen (O) content of 11%, as opposed to 1% or less in fresh petroleum samples, with the other elements—carbon (C), hydrogen (H), nitrogen (N), and sulfur (S)—present in the normal amounts. This indicates that the sample had been degrading for a long time within the amphora; apparently it had been there for 2,500 years. However, elemental analysis does not identify the kinds of molecules present in the sample. To do this, the researchers used ultrahigh-resolution mass spectrometry.

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