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Paul N Hengen pnh at cockleberry.ncifcrf.gov
Tue Nov 28 12:57:39 EST 1995

Nikolai Chitaev (nikolaic at VISAR.WUSTL.EDU) wrote:

:> Something wired happened to my SDS-PAGE gel. I did SDS-PAGE many times
:> before, but haven't done it for a while. Recently, when I adapted my old
:> protocal for a mini-gel, it takes hours for the separating gel to
:> solidify and even worse, the stacking gel solidified poorly and the wells
:> did not contain the samples very well as the result of it.

: Poor (slow) polimerization of acrylamide means that your APS is dead. If the APS is
: freshly made and problem persists - dead TEMED (instead to adding more TEMED buy new).

To test if the APS is too old, put some in a test tube and add the correct
volume of H20 to make 10 mg/ml. If you hear it snap, crackle, and pop, then
it is still good. At one time I looked into why it does this and all I could
figure is that some gas forms (I forget if it is hydrogen or oxygen?...somebody
please tell me which) within the crystals when water is added to APS which
causes them to pop. It is mentioned in Maniatis, but not explained why this

* Paul N. Hengen, Ph.D.                           /--------------------------/*
* National Cancer Institute                       |Internet: pnh at ncifcrf.gov |*
* Laboratory of Mathematical Biology              |   Phone: (301) 846-5581  |*
* Frederick Cancer Research and Development Center|     FAX: (301) 846-5598  |*
* Frederick, Maryland 21702-1201 USA              /--------------------------/*
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