Much of our expedition material was preserved in 70% ethanol (in a few cases
that means 140 proof rum!). The lots were split, with part kept in alcohol
and part desiccated for the dry collection. We do not have problems with
odor from these specimens.
 
Ideally you should use ten times the volume of alcohol as specimens because
water in the specimens dilutes the alcohol. If you have a jar half filled
with shells and you pour 75% ethanol in, the final concentration will be
under 50%.
 
If you plan to preserve specimens in alcohol, 70% ethanol is much superior
to isopropanol. Isopropanol hardens the animal to the point that it can't be
dissected. Ethanol higher than 80% also hardens the animal.
 
For DNA studies, methanol and ethanol are normally used, but isopropanol
should be okay. The alcohol denatures enzymes that destroy DNA, so the
higher the alcohol concentration (70% or more), the faster the enzymes are
stopped.
 
If you are purchasing ethanol that is not intended for drinking, it is
probably denatured by addition of chemicals that make it undrinkable. I
don't know what effect the denaturants would have on the specimens.
 
Gary
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Gary Rosenberg, Ph.D.                     [log in to unmask]
Malacology & Invertebrate Paleontology    gopher://erato.acnatsci.org
Academy of Natural Sciences               http://www.acnatsci.org
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