Scientists have relied on this technique since the 1600s to preserve the specimen or organ being studied. If done correctly, this technique can preserve samples for hundreds of years, according to the American Museum of Natural History.
“Alcohol is toxic to the kinds of microorganisms that would cause spoilage,” Bill Carroll, assistant professor of chemistry at Indiana University Bloomington, told Live Science.
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He used wine as an example, which is made because yeast eats sugar from grapes and then produces alcohol. The alcohol content of about 14% can help delay the growth of bacteria for years.
But preserving other organic materials such as DNA, body tissue or animal samples requires higher alcohol concentrations, says Katherine Maslenikov, fish collection manager at the Burke Museum in Seattle.
Maslenikov usually counts on alcohol , particularly ethanol, for long-term storage for some tissue samples for DNA analysis. Then the fish specimens were immersed in a jar containing 70% alcohol and 30% water.
“The water in the solution will keep the tissue hydrated, which helps the animal or specimen maintain its shape, and the alcohol will prevent the growth of fungi and bacteria,” he said.
It can be difficult to decide what percentage of alcohol to use because too much or too little can affect the shape and flexibility of the sample. Its ability to preserve the sample in solution will also be affected.
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