TBE Acrylamide/Formamide gels running slowly (View forum version)



Jeninie

Posted 19 January 2011 - 10:40 AM

Recently our PAGE gels have been running slowly, needing about 40% more time to reach necessary separation.

We have swapped out Acrylamide and Urea brands, and tried fresh APS, TEMED and TBE, with no luck.

Any ideas?

Thanks.


We run large scale PAGE gels (BioRad SequiGen 38x50cm) for DNA SSR analysis.
Usually 1.75h @ 110watts (1800V-2800V)

7% (19:1 acrylamide:Bis)
1X TBE
We use both "regular" acrylamide gels, as well as acrylamide+formamide, with the same results.

mdfenko

Posted 19 January 2011 - 11:30 AM

have you tried a different power supply? apparatus?

maybe the limits are changed or not outputting what you expect or the electrodes damaged or dirty.

Jeninie

Posted 19 January 2011 - 11:41 AM

We have 3 different BioRad power packs, and have recently purchased a new base unit (base with electrodes)

Unfortunately, it happens with all 3 packs, as well as the new and old base units.

phage434

Posted 19 January 2011 - 02:19 PM

How's your water? High salt in the water could cause this.

Jeninie

Posted 19 January 2011 - 02:42 PM

We have a 4-cartridge E-Pure system with Culligan pre-filter (the water originates from our building's de-ionized water supply).

Our cartridges are due for a change (thanks for the reminder)... but I can't imagine they're that bad yet.