Electrophoresis Buffers - Unlimited Lifespan?

Dr Engelbert Buxbaum engelbert_buxbaum at hotmail.com
Wed Dec 28 04:59:28 EST 2005


Wolfgang Schechinger wrote:

> At the moment, I am using an older type of the Hoefer SDS-PAGE
> apparatur and am running tris tricine gels. Upper buffer (cathode) is
> approx 500ml, lower buffer (anode) is estimated 2.5 liters, as I need
> it for heat exchange, too.
> 
> After 3 runs (4 gels in total), pH changed in both buffers for approx
> 0,4 units, so I wonder how long I may use them until re-using them will
> affect my results.
> 
> I thought of re-adjusting pH now. (fighting protons with NaOH and
> hydroxyl anions with HCl), 

That would increase the conductivity of the system, increasing heating.
> 
> In contrst, when one is using TrisGlycine systems, would it be
> sufficient to mix upper and lower buffer (which are the same *before*
> you run a gel and where H+ and OH- generated during the electrophoresis
> / electrolysis (!) should compensate each other after mixing? The same
> then should be true for TAE and TBE in DNA electrophoresis. 

The problem is not the OH- and H+ ions, which are balanced by other ions
even in the seperate upper and lower tank buffer. The problem is the
destruction of buffer compounds by side reactions during
electrophoresis.


> I am also looking for a really good paper that will explain the
> electrocheistry behind all that stuff - any refs in your forebrain?

Ornsteins (1962) original paper on discontinuous electrophoresis
explains things pretty well, for developing your own buffer systems you
should consult Jovins (1973) papers on the subject.


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