[NHCOLL-L:4914] Re: Isopropanol as a preservative

[Richard Rosenblatt]

Malcolm: Unlike ethanol, isopropanol is not a fixative. The fishes 
must have been fixed in formalin before being placed in iso.



>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 
><<mailto:rrosenblatt at ucsd.edu>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.
>2022: Soylent Green is People!
>
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