Hoefer SG15 - Manual (Page 7)

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p5
Pouring gradients from the bottom
This technique is commonly used in filling
multiple gel casting chambers.
1
Proceed as described on page 3, putting dense (final
or bottom) solution in the reservoir chamber (step 3)
and light solution in the mixing chamber (step 5).
2
Connect the delivery tubing to the bottom inlet of a
gel casting unit or to a cannula long enough to reach
the bottom of the receiving container. Adjust the
pump rate so that the solution is not forced up in a
“fountain” that mixes with the overlying solution.
3
If all of the gradient solution must be delivered to the
container, a displacement solution may be used. Just
as the last of the gradient mix is pumped out of the
mixing chamber, and before any air enters the tubing,
add an appropriate volume of a denser displacement
solution to the mixing chamber and pump it through
until all of the gradient mix has been delivered. It is
convenient to include a dye in the displacement solu-
tion to visually track the boundary between the gradi-
ent mix and the displacement solution.