[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

[dinosaur] Raman spectroscopy said to falsely identify organic molecules preserved with fossils




Ben Creisler
bcreisler@gmail.com

A new paper. Note that a number of recent dinosaur papers that identify organic traces have used this technique...

Julien Alleon, ÂGilles Montagnac, ÂBruno Reynard, ÂThibault BrulÃ, ÂMathieu Thoury Â& Pierre Gueriau (2021)
Pushing Raman spectroscopy over the edge: purported signatures of organic molecules in fossil animals are instrumental artefacts.
BioEssays (advance online publication)
doi: https://doi.org/10.1002/bies.202000295
https://onlinelibrary.wiley.com/doi/10.1002/bies.202000295


NOTE: A free preprint version of the paper from 2020 is available here:

https://www.biorxiv.org/content/10.1101/2020.11.09.375212v1


Widespread preservation of fossilized biomolecules in many fossil animals has recently been reported in six studies, based on Raman microspectroscopy. Here, we show that the putative Raman signatures of organic compounds in these fossils are actually instrumental artefacts resulting from intense background luminescence. Raman spectroscopy is based on the detection of photons scattered inelastically by matter upon its interaction with a laser beam. For many natural materials, this interaction also generates a luminescence signal that is often orders of magnitude more intense than the light produced by Raman scattering. Such luminescence, coupled with the transmission properties of the spectrometer, induced quasiâperiodic ripples in the measured spectra that have been incorrectly interpreted as Raman signatures of organic molecules. Although several analytical strategies have been developed to overcome this common issue, Raman microspectroscopy as used in the studies questioned here cannot be used to identify fossil biomolecules.

===