From:Gayle Callis

Was there no fixative, formaldehyde?? involved in this procedure at this
pH? If so, the formalin solution was left to break down (formaldehyde to
formic acid) due to poor buffering, no buffering, and low pH results.   

Acid solutions alone (containing no formaldehyde) can macerate soft tissues
off bones.  Acids are not fixatives, with the exception of picric acid in
small amounts and with controlled fixation times. The acids or very low pH
of a formalin fixative gone bad hydrolyze proteins, rendering nuclei
impossible to stain, plus other morphological damage.  One needs to use
neutral buffered formalin at pH 7 or so.  If bone is left in buffered
formalin with a pH lower than 6 or so, the bone will acutally decalcify
over time due to that formaldehyde converting chemically to formic acid. 

, At 11:33 AM 5/24/02 +0200, you wrote:
>Hi all
>What will happen if someone puts tissues or a dead animal in a acidic
>solution with a pH of about 2.7. Will this solution serve as a kind of
Gayle Callis
Research Histopathology Supervisor
Veterinary Molecular Biology - Marsh Lab
Montana State University - Bozeman
19th and Lincoln St
Bozeman MT 59717-3610

406 994-6367 (voice mail)
406 994-4303 (FAX)


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