[Histonet] NBF or paraformaldehyde

Wed Nov 30 10:53:53 CST 2005

Sarah,
Besides the various buffer components, nd assuming identical concentration,
functionally they are exactly the same - paraformaldehyde is just
polymerized formaldehyde. Commercial neutral buffered formalin may have
methanol added to prevent polyermization over long periods of time, but not
enough to make a difference in fixation. 

The reason to use paraformaldehyde to make your formalin is to control the
ingredients so you know what is in it. There may also be other ingredients
you wish to add for various experimental reasons. Therefore, it may be
better to use formalin you make yourself so you can control your experiments
properly. 

A commercial NBF (Carson's modified Millonig's buffered formalin) is also
excellent for electron microscopy.

For general pathology, any NBF is usually fine. 

Tim Morken
Lab Vision - Neomarkers
www.labvision.com

Free webhosting for US State Histotechnology Societies:
http://www.labvisioncorp.com/demowebsite/index.cfm

-----Original Message-----
From: histonet-bounces <@t> lists.utsouthwestern.edu
[mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of Pixley,
Sarah (pixleysk)
Sent: Wednesday, November 30, 2005 8:39 AM
To: histonet <@t> lists.utsouthwestern.edu
Subject: [Histonet] NBF or paraformaldehyde

Dear Histonet:
I should probably know this, but I don't, so I am asking. What is the
difference between using neutral buffered formalin and paraformaldehyde?
Does one give better morphology or better recovery of antigens for
immunostaining? I am a researcher, not a histotech, and I have always used
para. However, with all this talk of NBF, I am wondering why. I believe that
I have been told at one time or another that the crosslinking is better with
para, but since I am always doing immunostaining, I don't want strong
crosslinking.

I apologize if this is a totally "you should know" question. If there are
websites describing this, I would appreciate getting them, because that will
save me some time looking them up. Thanks, this is a great listserve!

Sarah Pixley
Univ. of Cincinnati

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