dialysis product needed

D. KIM dkim at NMSU.Edu
Tue Apr 14 10:18:12 EST 1998


I used to use the collodion bags from S&S.  Sometimes, however, dialysis
causes large amounts of water to go into the bag (at least, with regular
clipped bags, they pick up water and become "pressurized".).  With the
open top of the collodion bags, isn't there a chance that the bag will
overflow as it comes to equilibrium (with large concentration of the
macromolecule?).

Daniel Kim


Jeffrey A. Cohlberg <cohlberg at csulb.edu> wrote:
: Clemens Suter-Crazzolara wrote:
: > I am looking for eppendorf tubes with
: > a built-in dialysis membrane (I need to
: > dialyse very small amounts.
: We buy Sartorius SM 13202 K microcollodion bags, which are essentially 
: little 1-ml tubes with a wide lip, made of a semipermeable material.  
: You can make a holder for the bags by poking holes in the plastic lid of 
: the container with a hot 2-ml pipet -- this holder can then be used to 
: suspend the bags in a beaker.  You can then simply pipet as little as 20 
: µl into the bags and recover it quantitatively after dialysis is 
: complete.  The bags can be cleaned by soaking in 8 M urea and reused 
: more or less indefinitely.  Dialysis is slower than with conventional 
: dialysis tubing, but an overnight dialysis is sufficient to get to 
: equilibrium.  (By the way, I learned this trick on a sabbatical leave in 
: Franke's lab in your own institution -- stop by their lab for more info 
: -- maybe they'll lend you a few to try out.)
: -- 
: Jeffrey A. Cohlberg, Professor
: Department of Chemistry and Biochemistry
: California State University, Long Beach
: 1250 Bellflower Blvd.
: Long Beach, CA 90840
: phone (562) 985-4944	fax (562) 985-8557



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