Re: Removal of Bouin's before processing


I prefer to remove picric by water washing.  I wash the sample in running
deionized water post fixation for 10 minutes or so.  This usually does remove
the yellow color.  If picric is left in the tissue I have noticed some
brittleness after processing affecting the microtomy.

"Su, Phy-Huynh" wrote:

> Dear Histonetters,
> We have bovine tendons fixed with Bouins.  According to Luna
> (Histopathologic methods and color atlas of special stains and tissue
> artifacts) and Carson (Histotechnology), Bouin's should be removed before
> processing, whereas Sheehan Hrapchak (Theory and practice of
> Histotechnology) states that it will be removed in the 50% batch, so removal
> of Bouin's prior to processing is not necessary.
> What's the majority opinions of experienced users? Are 4 changes in at least
> 20 volume of 50% EtOH in 2 days enough to remove Bouin's?  The yellow color
> of picric acid is still there, even after several weeks in 50% EtOH, but it
> doesn't mean that Bouin's is not completely removed, does it?  If it's not,
> then how will Bouin's be efficiently removed before processing?  How do you
> make 70% EtOH saturated with Licarbonate???  I've tried to add 1%
> LiCarbonate solution into alcohol, starting at 100%, 95%, 70%, and then 50%
> EtOH.  LiCarbonate doesn't precipitate out easily in 50% EtOH only.  But the
> final concentration of alcohol is off course, nowhere near 70%.  100% and
> 95% alcohol will precipitate out LiCarbonate immediately, doesn't matter how
> minute the added volume.  According to the Merck index, LiCarbonate is
> "practically insoluble in alcohol".  I also tried to add some solid
> LiCarbonate to 70% EtOH, namely 0.05%.  It doesn't go into solution.
> Thank you for your input.
> Su

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