[NHCOLL-L:4913] Re: Isopropanol as a preservative

[malcolm McCallum]

The Arkansas State University Museum of Zoology has maintained fishes in
isopropanol for decades.
The hereptology specimens are kept in ethanol (after 24-48 hr fixing in
formalin) for various reasons, but the fishes are housed in isopropanol
and the preservation is pretty darn good.  I do not know if the fishes are
formalin fixed first.

Malcolm

On Sat, Jul 31, 2010 at 5:12 PM, Richard Rosenblatt <rrosenblatt at ucsd.edu>wrote:

> Amplifying HJ walkers brief comment, the Scripps Institution of
> Oceanography Marine Vertebrate Collection and  UCLA fish collections
> converted  to 50% Isopropanol in 1952. I came from UCLA and became curator
> in 1958 and continued the policy. The SIO collection now contains more than
> two million specimens, many of them delicate deep-sea fishes. We soon
> learned of the relative immiscibility of iso in water and the necessity to
> stir and bring preservative up to strength after washing out formalin. One
> advantage not often mentioned about iso is that when working with specimens
> it is not necessary to keep dipping them in water or spraying nearly as
> often as with alcohol specimens. When working with alcohol specimens you can
> see the scales curling and the fin-rays rapidly drying out under the
> microscope. I attribute this to the 50% water content as well as the lower
> vapor pressure of iso.
> Without belaboring the point, or entering controversies over possible
> chemical reactions, I can say that we have maintained our collection for
> more than 50 years in 50% isopropanol  with excellent results.
>
>


-- 
Malcolm L. McCallum
Managing Editor,
Herpetological Conservation and Biology

1880's: "There's lots of good fish in the sea"  W.S. Gilbert
1990's:  Many fish stocks depleted due to overfishing, habitat loss,
            and pollution.
2000:  Marine reserves, ecosystem restoration, and pollution reduction
          MAY help restore populations.
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