Just to add to the discussion, I was brought up to always make fresh
APS. During a continuing period of gel problems, I threw out all the
stock solutions and started fresh, only to have the problems continue.
At that stage, I concluded that it was time for a new bottle of APS - in
comparison the old APS looked rather yellow. That ended the problems.
The moral: When it comes to APS, if in doubt, throw it out (and always
make sure that the APS is white amd crackles when dissolved).
Jonathan B. Marder , Department of Agricultural Botany
E-mail: MARDER at agri.huji.ac.il | The Hebrew University of Jerusalem
Phone: (08 or +9728) 9481918 | /\/ Faculty of Agriculture
Fax: (08 or +9728) 9467763 |/ \ P.O.Box 12, Rehovot 76100, ISRAEL