RE: Eosin bleeding out

Molecular sieves are another way to dry out alcohol. Drierite and molecular
sieves only adsorb so much water and than they become ineffective and have
to be regenerated. To use these products properly it is important to know
the adsorption capacity and the moisture content of the liquid you are
drying out.  Figure out from there how much you will need to totally adsorb
the moisture.  It's best to dry out reagents right before use.

Rande Kline
EM Science

Robert Geske  on 08/09/2002 01:30:48 PM

To:    "'Johnson, Teri'" , "Histonet (E-mail)"
Subject:    RE: Eosin bleeding out

......."I find that it's nearly impossible, especially in the humid
conditions here, to keep the alcohol completely anhydrous."


have you considered the use of DRIERITE (anhydrous calcium sulfate) in your
absolute alcohols.  the color indicator will give you feedback on how
relatively absolute your absolute really is.


-----Original Message-----
From: Johnson, Teri []
Sent: Friday, August 09, 2002 11:48 AM
To: Histonet (E-mail)
Subject: Eosin bleeding out

I have this trouble using the xylene substitutes.  Most manufacturers say
you have absolutely anhydrous alcohol before your final clearing, this
be a problem. I find that it's nearly impossible, especially in the humid
conditions here, to keep the alcohol completely anhydrous. I'll get
of the eosin after staining three slides, even with 4 changes of absolute
reagent alcohol.

Having said that, I am evaluating Surgipath's Clearium, and am
directly out of absolute isopropyl alcohol.  It's too soon to tell if I
it unconditionally, but the bleeding problem seems to have stopped.  The
only problem I've noticed with it is air bubbles appear several hours after
coverslipping.  I suspect they were there all along, but just got bigger as
they sat.

Teri Johnson
Managing Director Histology Core Facility
Stowers Institute for Medical Research
1000 E. 50th St.
Kansas City, Missouri  64110

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