NA45 Paper DNA extraction problem

Tracy Aquilla aquilla at
Wed Aug 10 17:20:35 EST 1994

In Article <317aqm$rp8 at>, grieger at (David M
Grieger) wrote:
>I had my student try to purify a 200bp fragment from a gel using the NA45
>paper technique, recently discussed here on this news group.  After she did
>the hi-salt washes and the EtOH precipitation (+glycogen), there was no
>normal pellet but a nonaqueous "bubble" in the bottom of the microfuge tube.
> After adding TE and doing a second EtOH precipitation the same result
>occured.  Could this result from carry over from the hi-salt washes?  Any
>thoughts on this problem would be appreciated.  Thanks.

I use NA45 membranes, but I have never seen this phenomenon you describe.
The only thing I can suggest is leave out the glycogen. I never add it when
precipitating DNAs eluted in hi-salt NET buffer, and I never have this problem.

Tracy Aquilla, Ph.D.
Dept. of Molecular Physiology and Biophysics
University of Vermont, College of Medicine
aquilla at

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