[Histonet] RE: pfa vs. formalin
bhewlett <@t> cogeco.ca
Fri Aug 4 13:26:06 CDT 2006
There is NO such thing as a solution of paraformaldehyde.
As has been stated many times, paraformaldehyde is a solid polymerized form
When paraformaldehyde is dissolved in water, it de-polymerizes to form
The formaldehyde in turn hydrates to become methylene glycol.
10% NBF is, for all practical purposes, the same whether made from
commercial formalin (37-40% formaldehdye) or from solid paraformaldehyde.
----- Original Message -----
From: "Melissa Gonzalez" <Melissa.Gonzalez <@t> cellgenesys.com>
To: <jdr43 <@t> omega.med.yale.edu>
Cc: <histonet <@t> lists.utsouthwestern.edu>
Sent: Friday, August 04, 2006 2:03 PM
Subject: [Histonet] RE: pfa vs. formalin
I was taught by histotechs that 10%Neutral Buffered Formalin is the gold
standard vs paraformaldehyde, because it is optimally buffered to exchange
with tissue fluids during the fixation process, and that unbuffered
fixatives can result in artifacts which you may find microscopically in the
tissue slices after stainings. How major/minor this detail turns out overall
in the grand scheme of things, I don't really know. I've never seen the
direct compare and contrast, for example in H&E sections comparing both
I have found a supplier of 10% Buffered Paraformaldehyde, from Newcomer
Supply, which I use routinely for immunofluorescence of perfused, and
So then I would like to know, is there a technical difference between 10%
NBF (formalin) vs 10% NBP (paraformaldehyde)?
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