problem with casting PAG - large number of persistent air bubbles in a gel (May/21/2005 )

Hello,

I have encountered a weird thing while casting PAG for my AFLPs.

There are persistent air bubbles throughout a gel in such a number, that it becomes impossible to use a gel. This does not correlate in any way with the degree of cleanness of glass plates, namely the bubbles appear even after very thorough cleaning (few minutes with a brush plus hot water, 4 times DistW, 4 times EtOH). Yet, formerly there were no bubbles even after careless cleaning (1 time DistW, 1 time EtOH).

There are no recognizable sources of contamination with some hydrofobic substances neither in distilled water nor in special paper towels which are used for cleaning. All the steps in cleaning the the glass plates and composing the gel matrix are performed in the same way as in "the best days".

The problem made my work impossible. I will be unutterably grateful to any comments to the point, for my colleagues are as puzzled as myself about that.

Thanks.

Igor

Igor,

it may well help to resiliconise your glass plates as this made a world of difference to pouring gels with very minimal cleaning.

Also, this may not be a regular procedure nowadays, I normally degas my gel mixtures under a vaccum as this may also cause the spontaneous air bubble formation.

good luck!

Dear Methylnick,

I am very grateful to you for your useful comment.

Good luck with your researches!
Sincerely
Igor

Dear colleagues,

Thank you for your comments.

I am sorry, it is my fault that I have described the problem incompletely.

The tricky part is that the bubbles appear not in the volume of the gel, but rather due to uneven movement of the solution front while casting.

That is, there are no bubbles, but gel-free spaces between the glass plates.

Sorry for inaccuracy,
Igor

Igor,

resiliconising and acid washing will certainly help solve your problem.

Another way, when pouring your gel, I normally pour the gel with the plates horizontally positioned.

To avoid the bubbles forming at the front, i slowly inject the gel solution and tap the front when it looks like a bubble may form and the tapping usually prevents that from happening it's an art form that needs to be mastered!

Good luck!

Nick

Igor,

resiliconising and acid washing will certainly help solve your problem.

Another way, when pouring your gel, I normally pour the gel with the plates horizontally positioned.

To avoid the bubbles forming at the front, i slowly inject the gel solution and tap the front when it looks like a bubble may form and the tapping usually prevents that from happening it's an art form that needs to be mastered!

Good luck!

Nick

Who is resiliconisation done.
I have no idea?
Who is it going to help?
Thanks........

cheers
raj