[Histonet] Re: picric acid

[Bob Richmond]

Picric acid (trinitrophenol) is structurally related to
trinitrotoluene (TNT) but is much easier to synthesize, so it was used
as a military explosive earlier than TNT. Unlike TNT, which must be
detonated with a primer, picric acid can be detonated directly or even
explode spontaneously. It's the dry chemical that's explosive. Bottled
with 10% water, it's actually quite safe - it's when the water
evaporates that it gets dangerous.

In Europe World War 1 steel hand grenades, full of either picric acid
or TNT corroding into picric acid, are considered the most dangerous
of 20th century munitions that are still occasionally found on old
battlegrounds.

I was interested to read here on Histonet three accounts of actual
explosions of laboratory picric acid - I was never sure before that
these weren't urban legends - as well as of the truly horrible Halifax
disaster.

I don't think histology labs should keep solid picric acid at all. You
can either buy Bouin's fixative ready made or mix your own, using the
saturated solution of picric acid in water that's still available for
labs doing Jaffe reaction determinations of creatinine.

Bob Richmond