Re: chrome-alum gelatin
I cannot agree with you that chrome gelatin solutions for subbing slides
cannot be stored in the refrigerator - at least overnight. We give our
subbed slides 3-4 coats, drying between each for a more uniform coating.
We have stored the solution overnight in the refrigerator, allow to warm
to room temperature and use that day. There is no difference between
slides coated all in the same day and those coated partly on one day and
partly on the second. I think that the reactions that you refer to occur
with prolonged time and are minimal in solutions refrigerated overnight.
We also do not have infection with organisms and cannot think that this
would be a problem with overnight storage.
"J. A. Kiernan" wrote:
> On Sat, 28 Jul 2001, Sunil Thomas K wrote:
> > I have a question regarding chrome alum-gelatin used
> > for subbing. It gets very viscous when referigerated
> > (difficult to pour out from the glass bottle.
> > Is this solution warmed before slides are dipped?
> A smart observation, Sunil Thomas K !
> Chrome-gelatin solutions must be used soon after
> making. They cannot be stored in a fridge or
> anywhere else. They cannot be diluted either.
> Try this experiment. Make a chrome-gelatin solution
> and put 1 ml of it into a test-tube or similar vessel.
> Prevent evaporation with a bung, and after a few days
> add 10-20 ml of warm (about 40C) water. Shake well and
> observe. The gel, in which protein molecules are
> cross-linked by Cr atoms, cannnot be dispersed or
> dissolved in the water.
> Chrome gelatin solutions quickly become infected
> so they should be used right away and not stored.
> John A. Kiernan
> Department of Anatomy & Cell Biology
> The University of Western Ontario
> London, Canada N6A 5
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