Formalin vs. Paraformaldehyde - any difference?? (Jun/21/2007 )

At the beginning, many years ago, I used to prepare 4% PFA using paraformaldehyde as powder in PBS. Then I realized it was easier to use the already solved Formalin 37% and further dilute it (again in PBS, of course). But today I met with a technician that told me they are not exactly the same and that for fixing tissue it is better to use the homemade PFA from powder.

Have you ever heard about that?? I still don't think so, but I would like to know your view...

hallo,

I asked me the same question, then i found a link giving some explanations:

http://www.biology.duke.edu/lmcf/formaldeyde.html

At the beginning, many years ago, I used to prepare 4% PFA using paraformaldehyde as powder in PBS. Then I realized it was easier to use the already solved Formalin 37% and further dilute it (again in PBS, of course). But today I met with a technician that told me they are not exactly the same and that for fixing tissue it is better to use the homemade PFA from powder.

Have you ever heard about that?? I still don't think so, but I would like to know your view...

QUOTE (Radar @ Jun 21 2007, 01:00 PM)

At the beginning, many years ago, I used to prepare 4% PFA using paraformaldehyde as powder in PBS. Then I realized it was easier to use the already solved Formalin 37% and further dilute it (again in PBS, of course). But today I met with a technician that told me they are not exactly the same and that for fixing tissue it is better to use the homemade PFA from powder.

Have you ever heard about that?? I still don't think so, but I would like to know your view...

additionally, I want to say that in our lab we routinely use a ready-to-use Formaldehyde-Solution 4% which is neutral buffered and stabilized with methanol. but i think it is different from lab to lab.

additional information: http://swehsc.pharmacy.arizona.edu/exppath...ormaldehyde.pdf

We usually use formaldehyde 4% for fixing cells and for animal tissue, we use paraformaldehyde 4%.

when i worked clinical histology we used formalin as standard (by the bucket load)
now i'm doing research i use para powder in pbs freshly made each time i need it (10 ml at a time)

(thanks for the info moljul)

dom

I've made fresh formaldehyde solutions by heating paraformaldehyde - not my favorite process, but I didn't want to use formalin on my samples because of the methanol. I've now found two companies that make fresh formaldehyde solutions and seal it in ampules rather than adding formaldehyde to stabilize it. Both work well.

http://www.emsdiasum.com/microscopy/produc...rmaldehyde.aspx

http://www.piercenet.com/Products/Browse.c...;WT.mc_id=forum