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SORS Laser Scans Reveal Contents of Darwin’s Sealed Specimen Jars

The portable SORS method lets museums identify potentially hazardous preservation fluids without opening historic containers.

Overview

  • Researchers from STFC, the Natural History Museum in London, and Agilent used a portable spatially offset Raman spectroscopy system to analyze 46 sealed specimens from Darwin’s era.
  • The study, published in ACS Omega, achieved accurate fluid identification in nearly 80% of jars, partial matches in about 15%, and left only three cases unconfirmed.
  • Results showed common historical practices, with mammals and reptiles typically fixed in formalin then stored in ethanol, while many invertebrates were preserved in formaldehyde-based solutions that sometimes included glycerol.
  • The scans also identified the types of glass used for the historic containers, offering additional context for conservation and storage decisions.
  • The approach enables in-storage surveys of fluid collections, addressing safety and care across more than 100 million preserved specimens worldwide where openings could risk damage or exposure to toxic compounds.