exclusion threshold for PCR purification

David Micklem dmicklem at cmgm.nospam.invalid
Tue Dec 17 11:33:17 EST 2002

In article <3DFE3A92.7EB62F5F at dfci.harvard.edu>, denis dupuy
<denis_dupuy at dfci.harvard.edu> wrote:

>Hello everyone,
>I'm involved in a large scale PCR cloning project and I have trouble
>with contaminant bands that are about 100bp (which are primers dimers).
>I'm looking for a 96-well format protocol that would allow PCR
>purification of my genuine PCR product.
>All the usual kits are set up to retrieve PCR products as small as
>Does anybody know a way to modify this cuttoff so that I could retrieve
>only bigger fragments and get rid of my contaminant 100bp-species?
>Thank you in advance

Hi Denis,

How about PEG precipitation? You may need to play with the PEG
concentration to select the appropriate size range, but I think 10%
fails to precipitate 100bp but succeeds with 200bp.

See e.g. <http://www.invitrogen.com/content/Focus/181027.pdf>



D.R. Micklem,              Time flies like an arrow... 
Dept. of Genetics,          Fruit flies like a banana.
Cambridge University,      Email:drm21 at mole dot bio dot cam dot ac dot uk. 
Cambridge, UK              Phone: +44 (1223) 766336
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