May 24, 2012
Gold-plated Fossil Cleanup
A team from the University of Leicester has solved a long-standing problem in fossil research, and their novel approach will assist in the study of ancient specimens.
Fossils are often coated with a very thin layer of gold to study the specimens under an electron microscope. The gold brings out otherwise invisible details. When the analysis is complete the fossils need to be returned to their natural state. However, the removal of the gold has always been difficult, expensive, and uses toxic chemicals, including cyanide.
The chemists are developing electro-plating and polishing techniques with liquid salts called “ionic liquids” which are safe, cheap and environmentally friendly.
They found that ionic liquids can remove gold quickly and easily without damaging even tiny, delicate fossils. The liquids are safe to handle, can be simply disposed of, and can even dissolve the gold without affecting the glue that holds the fossil specimen in place for analysis.
Professor and geologist Mark Purnell said: "There are many cases where collecting the evidence required for research affects fossils or other objects in ways that might be considered as somewhat destructive — gold coating for electron microscopy falls into this category. Understandably, this creates problems for places like museums which have to balance the value of research on their collections against the risk that specimens will be affected. This approach to gold removal offers a new way of tackling this problem that is safe for both researchers and the specimens."
Professor and chemist Andy Abbott added: "This is a very nice demonstration of the use of ionic liquids for metal recovery but it is just the tip of the iceberg as we are using this technology for the recycling of a wide range of alloys and waste materials. The University of Leicester is building a strong reputation for the development of sustainable materials."
Details of the new technique are published in the journal Palaeontologia Electronica.