Gel melting, because of heating?

[Pavan]

Hi,

We have an agarose electrophoresis unit in the lab, which is kind of small and holds 80ml of buffer and 30ml of agarose gel and takes a run time of around 3hrs. The problem of it is that the gel melts during electrophoresis, it starts melting from near the wells.

Why is it so? We saw that amount of buffer used to decrease, but we used to fill it up. But still the same problem.

Then we thought of keeping the whole unit in a tray of ice. The ice gradually melted, but still the unit was in ice cold water! and still the gel melts. The unit was kept on a raised platform in the tray, hence the bottom of the unit also was getting cooled. But how can the gel melt so easily? Is it a problem with the electrode? what can be done of the unit now, is it a waste??

[lavendergirl]

Goodness, this should not happen. If you can, try decreasing the voltage as much as you can and perhaps decreasing the run time if possible. If not, I would buy a new unit, or call in a specialist to repair this one. Probably an issue with the electrode that causes a slowdown of energy transfer in one direction, pooling all of the energy in the form of heat in the buffer and thus melting the gel. You should not need to put the device on ice, it is clearly broken.

Hope this helps and good luck!

[butters]

what voltage was it running at? and what is ur buffer? tae? tbe? lb? what is the % of ur gel?

[admin]

It has happened to me before, you are making your buffer either too high or too low. Check carefully

[ramnivas]

Yes it happens sometimes so you should check what % gel, buffer and voltage??

[Pavan]

the buffer was 1X tae, and gel was 1% , voltage of 50v

[clevermizo]

Originally Posted by Pavan

the buffer was 1X tae, and gel was 1% , voltage of 50v

What's the separation between cathode/anode? The typical rule is your max voltage is 5V/cm. If your gel rig is very small, 50V may be more than this. If you have to run it hot, why don't you just run the gel in a cold room? Have you tried running it at 25V? 15V? Does it still melt?

[Drekketh]

Originally Posted by clevermizo

What's the separation between cathode/anode? The typical rule is your max voltage is 5V/cm. If your gel rig is very small, 50V may be more than this. If you have to run it hot, why don't you just run the gel in a cold room? Have you tried running it at 25V? 15V? Does it still melt?

Thumbs up! Though again from my experience on 50V shouldn't happen at all. In my lab I run gels cast in a glass (less than 1mm thin) and I do not encounter the melting prob. I would recommend you to prepare your TAE buffer again using Tris from another lab. Your problem is with your buffer.

[Multiplexion]

You have to decrease the voltage!