Hoefer SG500 - 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 in Section 1, putting dense
(final or bottom) solution in the reservoir chamber
(step 3) and light solution in the mixing chamber
(step 5).
2
In step 2, connect the outlet 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
solution to visually track the boundary between the
gradient mix and the displacement solution.