Re: glutaraldehyde

From: Katharine Thayer <kthayer@pacifier.com>
Subject: Re: glutaraldehyde
Date: Tue, 16 Mar 2004 13:58:59 +0000

> Ummm, so what you're saying is that this product that's marketed as a
> sterilizing agent can't sterilize anything at the pH it's packaged at?
> Brilliant!

So those products come with a small bottle of activator, which must be
mixed in just before use. For hardening gelatin, you don't need to use
it. (I described one of these products in detail a while ago.)

> This logic reminds me of something I read in the archives on the same
> subject (glutaraldehyde) which said, if I remember right, that one
> should use a plasticizer like glycerin to keep the gelatin from getting
> brittle, but the glycerin diffuses out of the gelatin in wet processing
> and the gelatin gets brittle anyway.

Plasticizer is a different issue. Gelatin becomes brittle in absence
of plasticizer when dried, regardless of hardener.

Glycerol is a very classic plasticizer but photographic industry
quickly realized that it was insufficient because it is diffusible.
More effective plasticizers such as ethylene glycol derivatives don't
have that problem. I talked about these things in a bit more detail a
while ago.

--
Ryuji Suzuki
"All the truth in the world adds up to one big lie." (Bob Dylan 2000)