I think self-oxidation of acrylamide should be another reason.
In my experience, the pre-mixed stacking gel with an approx.
neutral pH is much more stable than the pre-mixed separating
gel which has a quite basic pH. The reason may be that self-
oxidation occurs easier in the basic liquid. I stock only the
stacking gel (4%).
At 12:44 99-3-16 -0500, you wrote:
>Hi. I mostly agree with other's opinions. I also stock each solution
>separately for running gel, but in the case of stacking gel, I combine
>everything except APS and TEMED in dark bottle and store at 4 degC, because I
>always use same % for the stacking gel and it's somewhat bothering to mix
>small amount solutions every time. And the final 0.1% SDS in this mixture has
>never been precipitated. So, I think you might try to combine all the
>solutions (of course except APS and TEMED) for running gel too, if you
>use a single % acrylamide. For stability or self-oxidation of acrylamide, I
>have not much idea.
>>"J.S. Good" wrote:
>>> Any reason why one shouldn't mix acrylamide, buffer, water, SDS and use
>> this as as a stock solution, adding APS and TEMED at the last minute to an
>> aliquot prior to casting the gel?
Shanghai Institute of Biochemistry
Chinese Academy of Sciences