[Histonet] serra's fix question

Geoff McAuliffe mcauliff <@t> umdnj.edu
Fri Aug 31 13:12:43 CDT 2007

Hi Emily:

    Formaldehyde is a gas dissolved in water. Serra's fix is just 
another variation of formalin-alcohol-acetic acid, which is water based. 
If your mix is milky something is wrong. Buy fresh reagents.


Emily Sours wrote:
> We have a protocol for fixing chick embryos in Serra's fix (6 100% ethanol:
> 3 37% formaldehyde: 1 glacial acetic acid), which states that after fixing
> for one to four hours, the tissue should be washed in 60% ethanol then
> worked up to xylene.  What I don't understand is placing the embryo into a
> water-based wash when it was fixed in a non-water-based solution.  At first
> I thought the 37% formaldehyde might have water, but if any water is added
> to the Serra's fix, it becomes milky.  Am I missing something here?
> Emily

Geoff McAuliffe, Ph.D.
Neuroscience and Cell Biology
Robert Wood Johnson Medical School
675 Hoes Lane, Piscataway, NJ 08854
voice: (732)-235-4583 
mcauliff <@t> umdnj.edu

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