plastic disposable columns

tan at tan at
Wed Mar 16 11:15:41 EST 1994

In article <79712.a.hanly at> "Allison Hanly"
<a.hanly at> writes:
>Song Tan  <tan at> wrote:

>>Slight tangent to this discussion, but has anyone successfully used these
>>BioRad biospin columns with plasmid DNA?  I use Sepharose CL-4B or S400 spun
>>columns as the last step in my plasmid minipreps but when I tried using these
>>resins in the BioRad biospin columns, I got no DNA back in the spun column
>>"eluent".  Recovery from the home made spun columns (siliconized glass wool to
>>plug a Gilson blue tip) was fine, so I attributed the loss to the biospin
>>columns.  Would be nice to hear others' experiences.
>What rotor type did you use?
>Boehringer sell a similar column packed with sephadex for probe purification
>their protocol uses swing out buckets rather than a fixed angle rotor.
>Excerpt from product spec sheet
>" In a fixed angle rotor, the sample is likely to slide down the sides of the tube instead of
>flowing through the medium. This results in poor retention of nucleotides and decreased recovery of
>sample "
>Just a thought

I wish that was the problem, but I was using a swing out bucket rotor in the
experiment I described.  My guess is that the BioRad biospin frits are trapping
the plasmid sized DNA, but I don't have any proof for this interpretation
beyond what I mentioned already.

Any other experiences using BioRad biospin columns with kilobase sized DNA?

Song Tan
Institute for Molecular Biology and Biophysics
ETH-Honggerberg (Swiss Federal Institute of Technology)
8093 Zurich, Switzerland
email:  tan at

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