Denatured alcohol for histologic use:

Pure ethyl alcohol (ethanol) is the standard alcohol for histologic use, but,
because it is possible to drink it (anecdotes on request), using it requires a
lot of administrative hassle. Some histology services are able to delegate
this hassle to the hospital pharmacy, which however has to have adequate
locked storage space.

Ethyl alcohol is rendered (legally) undrinkable by naturing it. The Bureau of
Alcohol, Tobacco, and Firearms (BATF, under the Treasury department of the US
Gummint) has a large number of official denaturing formulas.

Alcohol S3DA is denatured with 5% methanol. For histologic use, it also has 5%
isopropanol added (I don't know why), and this is S3DA Modified. This mixture
is the usual one called Reagent Alcohol in histology. I believe that this is a
generic usage, and not a trade name.

Another denaturant for histologic use is methyl isobutyl ketone (MIBK). The
major problem with this denaturant is that it smells bad.

Ethanol denatured with acetone is sometimes available in laboratory catalogs.
It strips out eosin very rapidly.

As far as I know, reagent alcohol can be used for any histologic purpose for
which ethyl alcohol is specified. I don't know what happens to it, either
chemically or governmentally, if you distill it with a spinning band still and
try to re-use it.

Bob Richmond
Samurai Pathologist
Knoxville TN