[Nhcoll-l] 95% vs. ~70% EtOH?

[Sonia Rowley]

Dear List

I am writing with regards any experience and evidence for and against the
use of 95% or ~70% EtOH for longterm invertebrate (specifically gorgonian
coral) specimen preservation for collections. More and more institutions
seem to be turning to 95% EtOH, however, there are numerous conflicting
thoughts and evidence with regards the use of higher concentrations for
longterm specimen storage. Furthermore, I understand that there are 2 types
of high EtOH concentration; clean and dirty with the latter being far
cheaper but unsuitable for genetic analyses.

Whilst collections are indeed a taxonomic concern, this does include the
use of molecular work as part of the suite of tools in determining species
differences. The collections I have worked in using ~95% EtOH have had good
success with both storage and genetic work, but these specimens may often
be a maximum of 1 - 2 decades old. Conversely, others mention caveats such
as the high concentration dehydrating the specimen to such an extent that
it disrupts the integrity of both specimen and DNA. At the same time the
often high water content of specimens is said to bring down the EtOH
concentration which may also cause issues with specimen degradation.

Please excuse the somewhat rudimentary nature of my question, there does
seem a tremendous amount of confliction in what is recommend and therefore
it would be really valuable to hear what people have to say and recommend
from the list.

Thank you for your time with this matter and look forward to hearing any
responses

Sonia

-- 
Sonia J. Rowley PhD
Research Affiliate
Bernice Pauahi Bishop Museum
1525 Bernice St, Honolulu,
HI 96817,,USA
+1 808 348 6224

Research Affiliate
University of Hawai'i at Manoa
2538 McCarthy Mall, Edmondson 312
Honolulu, HI 96822
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