RE: [Histonet] Formaldehyde + Acetic Acid

From:"Lee & Peggy Wenk"

Thanks for the nice words, but unfortunately, my answer was based on my own
real life error.
Some years ago, I was making alcoholic formalin for the tissue processor. I
had already mixed the alcohol and water, then poured in the formaldehyde.
And watched it turn cloudy milky white, to my utter amazement. My thoughts?
- it's never done that before
- I wonder if it will go away if I wait a couple of minutes (no)
- I wonder if it will go away if I swirl the container and mix the solutions
better (no)
- I wonder what's wrong with the water today (no idea why I thought the
water was the problem)
Finally, I thought about looking at the labels on the solutions, and found
that I had inadvertantly grabbed the 10% NBF instead of the 40%
formaldehyde. Fortunately, I hadn't ruined any tissue, and all I had to do
was make up new alcoholic formalin using the correct chemicals.
However, that episode did teach me what can happen when I don't check each
label before I use a chemical. And, I did get to see what happens when
buffering salts and alcohol are mixed together. And this mistake then
allowed me, many years later (now), to help Jennifer figure out her
cloudiness problem.
Peggy A. Wenk, HTL(ASCP)SLS
William Beaumont Hospital
Royal Oak, MI 48073


From: Rene J Buesa [] 
Sent: Wednesday, May 21, 2008 9:29 AM
To: Jennifer Johnson;;; Elaine Smith
Subject: RE: [Histonet] Formaldehyde + Acetic Acid

Peggy showed why she had been awarded "Histotech of the Year" with her very
clever and insightful answer. 
The salts dissolved in the NBF will precipitate with the alcohol. That is
why the tissue processors have to be cleaned with hot hater (to eliminate
the salts by dissolving them), or why some people (like me) used to use 10%
formalin NOT buffered in the first 2 stations of the VIP (to avoid the salt
René J.

Jennifer Johnson  wrote:

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