Home-made Glass Milk

Sat Oct 5 09:37:39 EST 1991

Re: Use of glass beads to purify DNA from TBE gels
Attempts to use glass beads to isolate DNA fragments from TBE gels
often gives variable results depending on the TBE batch used for the gel.
Millipore has developed an immobilized glass containing filter that they
use to isolate DNA via the NaI method. They claim it works well with TBE
gels if: you add Na-phosphate,pH 6.5  to 100mM final concn. We use this
routinely and have no problems with TBE gels.
Apparently, the TBE problem is pH dependent and batch variable. Addition
of a buffer at lower pH cures the problem.
The composition of BIO-101's TBE modifier is unknown, but you may ;-)
be able to substitute a less expensive and readily available PO4 buffer.
Good luck
Don Back
Department of Biochemistry
Queen's University
Kingston, Ontario

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