hope you have some clue. I prepared a 5% acrylamide gel for DNA separation using s(at least I think!) same reagents as usual: acryl. 29:1, 10% aps, etc. Gel polymerised, but when I loaded the dye (standard) for the prerun to clean the gel, I saw that Bromophenol blue and Xylene cyanol co-migrated and did not separe as usual!
I have no idea what happened, reagents were the same but acrylamide (not prepared by me, but at least it polymerised): do you have some?