bright specks in EtBr stained gels - out, damn'd spot!

Klaus Salger salger at
Tue Feb 18 15:36:26 EST 1997

Sam Michaelson (sam.michaelson at wrote:
: Dear Netter Nutters

: I've recently been having problems with very intense small bright spots 
: showing up on agarose gels stained with EtBr.  I'm running 1.5% gels in 
: TBE, and staining the gels in 0.5 ug/ml EtBr after the run.  I thought it 
: might be dust or crud getting into the mix; I'm using mol.biol. grade 
: agarose, and filtering the TBE carefully before use, although this hasn't 
: completely removed the problem.  I'm trying to produce gels of a suitable 
: quality to be photographed for a poster.  Has anyone else had this 
: problem, and if so, how did you tackle it?

: Sam Michaelson
: bewildered biochemist now masquerading as molecular biologist


if your solutions do not contain any particle than maybe there's some dirt
in your staining tray. We've had a similar problem which was solved by
cleaning the tray.
It's also better to prevent the gel from sticking to the tray. This will
ensure homogene staining and prevent the gel from picking up stuff
from the tray. (Add the staining solution before the gel.)


Klaus Salger		phone : +49 (0)89 5902 	-502
Zoologisches Institut	FAX   :			-450
AG Wetterauer		e-mail: salger at
Luisenstr. 14
80333 Muenchen


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