Forskare har utvecklat en lasteknik för att undersöka innehållet i Charles Darwins ursprungliga prover från Galápagosöarna utan att störa de nästan 200 år gamla burkarna. Metoden, känd som Spatially Offset Raman Spectroscopy, avslöjar den kemiska sammansättningen av konserveringsvätskorna i förseglade behållare. Detta genombrott hjälper museer att bevara känsliga samlingar världen över.
Charles Darwin samlade prover under sin resa med HMS Beagle från 1831 till 1836, inklusive prover från Galápagosöarna som bidrog till hans teorier om evolutionen. Dessa föremål, som nu är konserverade i burkar på Natural History Museum i London, inkluderar däggdjur, kräldjur, fiskar, maneter och räkor. Ett team av forskare har nyligen studerat 46 av dessa historiska prover med en icke-invasiv metod för att undvika risker förknippade med att öppna behållarna. The technique employed is Spatially Offset Raman Spectroscopy (SORS), a portable laser method developed at the Science and Technology Facilities Council's Central Laser Facility and commercialized by Agilent Technologies. SORS directs laser light through the jar walls, analyzing scattered light to identify chemical signatures of the fluids inside. The analysis showed that preservation methods differed by organism type and era: mammals and reptiles were typically treated with formalin before storage in ethanol, while invertebrates used varied solutions including formalin, buffered mixtures, or additives like glycerol. The method accurately identified fluids in 80% of cases and provided partial results in 15%, also distinguishing glass from plastic containers. This collaboration between the Science and Technology Facilities Council, the Natural History Museum, and Agilent Technologies offers a new tool for managing over 100 million liquid-preserved specimens in global museums. Dr. Sara Mosca from the STFC Central Laser Facility noted: “Until now, understanding what preservation fluid is in each jar meant opening them, which risks evaporation, contamination, and exposing specimens to environmental damage. This technique allows us to monitor and care for these invaluable specimens without compromising their integrity.” Wren Montgomery, a research technician at the Natural History Museum, added: “As part of NHM Unlocked, here at the Museum we can analyse jars containing specimens without opening and disturbing their integrity. This work is the next step in demonstrating the Museum's commitment to transforming the study of natural history. Analyzing the storage conditions of precious specimens, and understanding the fluid in which they are kept, could have huge implications for how we care for collections and preserve them for future research for years to come.” The findings were published in ACS Omega on January 13, 2026.