ETBr in Loading Buffer

Michael Witty mw132 at
Tue Feb 5 07:08:02 EST 2002

On Tue, 5 Feb 2002, Krzysztof W. Wasowicz wrote:

> On Mon, 04 Feb 2002 19:40:19 -0800, D Picton <pictond at>
> wrote:
> >I was wondering if anyone has ever tried or knows why Ethidium Bromide
> >is not added to Loading buffer? I've never run across an article where
> >Ethidium Bromide is present in the Loading Buffer, it's allways
> >present either in the gel or as a post electorphoresis step.
> >
> >D Picton
> I tried using EtBr in loading sample when running PCR reactions. The
> staining was poor and EtBr seemed to affect migration of my samples.
> However, I use EtBr in the sample when I run RNA preparations in
> standard TBE agarose gel. Works like charm.

. . . I think ErBr intercalates, makes the helix untwist a little and this
affects shape and therfore migration.  Also, if EtBr is just in the
loading buffer it would be depleted during a run and become separated from
the DNA - all leading to poor electrophoresis.  Mike.

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