Poor resolution when isolating ssDNA?

[cheetah.zao from gmail.com]

70% enthenol precipitation in the presence of 50 mM MgCl2 may work.



On Jun 13, 5:56 am, Evan Reed <evan.g.r... from gmail.com> wrote:
>         Hej,
>
>                 I am trying to isolate ssDNA after binding dsDNA oligos with
> biotinylated antisense strands to strep microbeads, denaturing with
> NaOH, then adding the supernatant containing the sense ssDNA to a
> NAP-5 sephadex desalting column.  Unfortunately, I am getting terrible
> resolution when I try to elute on the column -- even after 2 mL of
> elution, I am still getting detectable levels of ssDNA in the eluate
> (dsDNA oligos of the same length elute just fine in 0.5 mL, with
> acceptable resolution).  The amount of DNA loaded into the column
> should be well below the binding capacity so I am not sure why this is
> happening.  Has anyone done this before?  Is there a better way to
> purify the ssDNA instead of this column?
>
> Thanks,
>
> ER