painful gel loading???!!!!!!

Andy Phillips andy.phillips at bbsrc.ac.uk
Fri Jan 31 05:20:28 EST 1997


xudong huang wrote:
> > >
> > >> I have a painful problem about agarose gel loading. The DNA samples do
> > >> not stay at the bottom of wells, intead, they float out of wells and
> > >> diffuse into the buffer. The loading buffer I use is 6XBPB, the gel
> > >> running buffer is 1X TBE. It is not because of air bubbles or oil

I had this recently, again with gel tank buffer used several times.  We re-use our buffers 
over & over, and I've seen people top up the tank with fresh 1xTBE to replace water lost by 
evaporation (the tank tend to get left with the lids off). If you do this many times over, 
the concentration of the TBE in the tank will increase, as will the density (you will also 
see an increase in the current for a given voltage). Eventually the gel buffer will have a 
higher specific density than the samples, causing the loss of sample that you see.

Sounds convincing?

Andy


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