We used the versene for several years, but when we starting doing
5'Bromo-2'deoxyuridine, found that it interfer with the antibody to the
BrdU.  It is not as pure, but definitely much cheaper.  I think I finally
sent the last of ours out with hazadous waste to get rid of it.

Patsy Dunn-Jena
Indiana University
Bone Research Laboratory
padunnje@iupui.edu

> ----------
> From: 	Barry Rittman
> Sent: 	Monday, April 30, 2001 12:46 PM
> To: 	histology
> Subject: 	EDTA
> 
> There appears to be a lot of confusion re EDTA.
> 
> EDTA is the acid itself and it is only slightly soluble in water.
> It has four potential sites for attachment.
> The salts that are formed e.g. sodium EDTA vary with the pH of the
> solution e.g.
> mono-sodium, disodium, trisodium, tetrasodium EDTA.
> I don't have the exact figures in front of me but mono around 3.65,  and
> tetra sodium EDTA around pH 11.
> When you prepare a solution for demineralization, it makes sense to use
> the disodium and then adjust the pH with HCl or NaOH to 7.2 or whatever.
> This solution then contains a mixture of di and trisodium EDTA.
> Concentrations cited vary from 5% through 20%. The concentration is not
> as important as agitation and/ changing solutions. Considering the cost,
> changing the solutions may be the cheapest route. If demineralizing
> large blocks then maceration can occur after some months. If there is
> danger of this, tissue can be "refixed" and then placed in new EDTA
> solution. Using various resins or HCl to speed up the process have not
> been shown to be effective. HCl is a poor demineralizing agent  for
> blocks of tissue.
> Using fixative (e.g. glutaraldehyde) in with the EDTA to prevent
> maceration slows down the demineralizing process dramatically.
> Can make the solution in phosphate buffer if you wish (this is routinely
> used in tissue culture made in PBS).
> There is probably no reason that di-potassium EDTA (versene) used some
> years ago in blood work could not be used and might be cheaper than
> di-sodium EDTA
> Barry
> 
> 
> 
>