EDTA shinks DEAE-Sephadex resin?

Tue Sep 3 09:48:31 EST 1996

On Sun, 1 Sep 1996, Ming-Ching Hsieh wrote:

> Dear Netters:
> I used a phosphate buffer, pH6.0 containing 3mM DTT and 10mM EDTA to 
> equilibrate a DEAE-Sephadex column, but the resin was shunk to at least half 
> of its original volume. I know the swelling properties of this resin are 
> dependent on ionic strength and pH. Indeed, the pH of the eluent was only 4.1, 
> suggesting a pH effect. More suprisingly, this effect seems irreversible 
> since 0.05M sodium chlorid in distilled water can not regenerate the resin. 
> The question is why EDTA changes the pH of this particular resin, and what's 
> the mechanism of it. Any idea is appreiciated. Thanks in advance.

My question is: Why are you using phosphate buffer for an anion-exchanger 
and how are you dissolving EDTA at that low pH?

			  Dr. Hiranya S. Roychowdhury
   			  Plant Genetic Engineering Lab.
			  Box 3GL, NM State Univ.
			  Las Cruces, NM 88003
			  Phone: (505) 646-5785
			  hroychow at nmsu.edu

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