Bio-Rad PROTEAN II XL Cell - Manual (Page 18)

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3. Stand the casting stand up on a level surface, add APS and TEMED to the monomer solutions, and
begin pumping the gradient monomer solution.
4. Once the gradient is poured (this should take no more than 10 minutes from the time the initiators are
added to the first monomer solution), withdraw the needle from the gasket, and immediately clean the
gradient former, tubing, and needle by pumping distilled water through them.
5. Overlay the monomer solution (see Section 4.1), or insert the comb (see Section 4.2), depending on
whether the gel is discontinuous or continuous, respectively.
Pouring Gradient Gels by Top-Filling
1. Attach the gradient maker tubing to a needle (catalog number 165-1943), a long cannula, or a piece of
tubing that will fit between the glass plates of the gel sandwich.
2. Insert the needle, cannula, or tubing as far as possible into the sandwich, and center it.
3. Add APS and TEMED to the monomer solution, and begin pumping the gradient. As the monomer level
in the sandwich approaches the tip of the needle, withdraw the needle slowly, so that it always stays
above the monomer level.
4. Immediately rinse any remaining monomer out of the needle by pumping water through the gradient
former and out the needle.
5. Overlay the gel, or insert the comb, as outlined in Sections 4.1 and 4.2, respectively.