resin decalcification

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From:Gayle Callis <> (by way of histonet)
To:histonet <>
Date:Fri, 2 Apr 1999 03:09:27 -0500
Content-Type:text/plain; charset="us-ascii"

Fisher sells a resin that is an equivalent, called Rexyn-101.
I have a recipe that was used until the solution turns green, a
nice built in indicator, and you will not be able to do chemical endpoint
determination, but if you have an xray machine, FAXITRON, it would be
very helpful to know when you have totally removed the calcium.
some people try to restore the resin with tedious, messy washes and the
gal who gave this workshop, just tossed the resin and made up new.
This a dilute formic acid mixture, approximately 5% and will take you a LONG
time.  One could probably up the formic concentration to 10%, even 15% but the
resin would be exhausted sooner (it is there to capture the calcium released
by acid, therefore chemical endpoint test is not possible)

This is a nice mixture from a workshop some years ago

Rexyn 101 (H)   500 grams, Fisher cat no. R203-500
Conc formic acid (88-90%)     200 ml
distilled water 3800 ml
Can re reused until the solution turns green, the resin was discarded and
a new mixture of solution is made.

This worked for a very small nasal turbinate slices in rat, gentle with
excellent results. They ultimately did Brdu staining.

If your bone is large, you could just increase formic acid to 10 - 15% in
water, forgo resin and expense, and do endpoint determinations to know
when calcium is gone. If you control the decalcification, most decalcification
methods will work faster for you on a large specimen.

Be sure you suspend your specimen in center of solution so the decalcifier
surrounds bone.  Their rat nasal turbinates and femurs took 7 days to
decalcify, which gives you an idea on how long your huge jaw will take!
They also housed a stirring bar inside a mesh screen to have agitation,
you can also bubble air in solution to do the same thing.   VWR and
Fisher have some excellent large 5 liter beakers with handles, made of
polyethylene, very safe, large, cheap and easy to handle.

Good luck,

Gayle Callis

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