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Help with electrophoresis - Phosphate ester electrophoresis (Sep/12/2005 )

Hi I'm just starting to learn how about the uses of electrophoresis, i'm applying the technique to sperate out phospate esters.

I ran a trial on friday and left the gel slab out over the weekend and when I came in this morning (monday morning) I found that the agar had shrunk in size by about 15-20%. The gel was a 2% agar using a 1% buffer solution of TAE at a pH of 9.5- i know i forgot to neutralise.

My problem is that I can't understand why the agar shrunk as whenever I have used it before it has never undergone such a change. I'm hoping someone has had this happen to them before or knows why it happened- my only thought is that its some strange reaction between the ethidium bromide and or the buffer with the agar, I don't think its down to water loss as this never happens when I've cultured bacteria over a weekend at 30 degrees centrigrade.

Another puzzling aspect of this is that the agar is alot more flexible than any other slabs I have made.
I would appreciate any help thanks Chris


I think it probably is water loss if you left the agarose gel out on the bench. If you want to pre-pour a gel and use it later, either leave it in a gel tank covered in buffer or wrap it in cling-film and put it in the fridge. I guess if you have already run it and want to store it wrap it in cling and put it in the fridge.

I'm guessing agar plates don't dry out as quickly because the lid reduces evaporation from them.

I remember leaving agarose gels in gel tanks which were low on buffer and coming back to find them shrivelled up.

All the best,