[Nhcoll-l] Different alcohol preservatives for vertebrate specimens - advice requested

[Julia Wilson-Davey]

Hello NHcoll colleagues,

I’m after some advice on the pros and cons of preserving vertebrate specimens in ethanol versus isopropanol.
I work in a museum fish collection. For historic (and financial) reasons, we store our large fish specimens in tanks of isopropanol. Sometimes, when we lend them to other institutions the receiving institution doesn't have the facilities to store them in isopropanol and so store them in ethanol. Does anyone know what is the consequence of having fish specimens preserved long term in 55% isopropanol, then sent on loan and stored in 70% ethanol? When they are returned to us, we put them back into the same tanks of isopropanol. Does stepping (laddering) them in isopropanol (30%->40%->50%) once they return reduce any negative effects on the specimens? What is the best approach for managing this transition between preservatives?

What is people’s experience storing vertebrate specimens in isopropanol versus ethanol, in general? As mentioned, our large specimens are stored in isopropanol, but our small specimens are stored in ethanol. In the next 2-3 years we will need to move the collection into a new facility and to do so will have to drain the isopropanol out of the large storage tanks. This is an opportunity to consider whether we should replace isopropanol with ethanol - so the whole collection will be stored in ethanol. What is people’s advice on this? Overall, we are currently happy with the condition of the specimens in isopropanol and like how they are not as brittle as ones stored in ethanol.

Thanks
Ngā mihi, Julia


Julia Wilson-Davey  | Kaitiaki Taonga Collection Manager Natural History
Museum of New Zealand Te Papa Tongarewa,
55 Cable Street, PO Box 467, Wellington, New Zealand
P (+64) 021 726 904 | E Julia.Wilson-Davey at tepapa.govt.nz<mailto:Julia.Wilson-Davey at tepapa.govt.nz> | W www.tepapa.govt.nz
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