Here's a letter I am posting for Barry:
Sent: Wednesday, January 08, 2003 8:59 AM
Subject: RE: Formaldehyde nomenclature (was Help with a fixative)
I think that the real question is whether it makes any difference if
concentration is 3.7 or 4%. The answer is that it does not. Formalin
solutions, and in fact most fixatives, have excessive amounts of
agent for the purpose of say cross linking proteins.
The problem with formalin solutions is that if they are stored for a
long time, formaldehyde oxidizes partially to formic acid. If this is
then used in an unbuffered solution there are all sorts of problems
the fixation picture.
If you wish to be a purist, you can just use the vapor to fix small
Sent: Wednesday, January 08, 2003 8:29 AM
To: Laurie Reilly
Subject: Re: Formaldehyde nomenclature (was Help with a
Formaldehyde is a gas - Full strength formalin, is a liquid -
37-40% formaldehyde in water.
10% Formalin (made from full strength formalin) used for
fixation is 3.7-4% formaldehyde.
Why is that so hard?
01/07/2003 10:13 PM
Subject: Formaldehyde nomenclature (was Help with a
The confusion surrounding the use of the words "formalin" and
"formaldehyde" is obvious from Charles' question and Katri's
The undergraduate and graduate students at this University have
much trouble and I find myself frequently having to reach for
paper to give an explanation, which is hopefully, but not
May I suggest a radical solution to the problem?
We could take the word "formalin" out of the English language.
Then the concentrate would remain as 40%Formaldehyde solution
fixative we commonly use would be 4% Neutral Buffered
Formaldehyde. I am
now labelling containers with 4% Buffered Formaldehyde and 10%
because that terminology is so ingrained. How many generations
do you think
it might take to change the mindset away from "formalin"?
07 4781 4468
Physiology & Pharmacology Fax 07
Aust.Inst.of Tropical Vet.& Animal Sc.
James Cook University
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