6 running the gel – Hoefer SE250 User Manual
Page 20
Important! After initial
monitoring, do not leave the
unit unattended for more than
45 minutes before checking the
progress of the the bands and
the buffer level.
3.6 Running the gel
Gels may be run at either constant current or
constant voltage. A constant current setting is
traditionally used with a discontinuous buffer
system so that the rate of electrophoretic
migration remains unchanged throughout the
run. Under these conditions, voltage increases
as the run proceeds. A lower current setting
is recommended for higher resolution. Precast
gels are run under the same current and voltage
conditions as self-cast gels.
It takes about one hour to run two 7 cm ×
0.75 mm Laemmli gels at 40 mA (20 mA per gel,
constant current). Check band progress after
5 minutes, and again after half an hour, keeping
an eye on the position of the tracking dye. The
run is complete when the tracking dye reaches
the bottom of the gel. Watch the buffer level
in the upper buffer chamber and, if necessary,
replenish it before it falls below the level of the
notched plate. (A small volume of buffer may
leak past a chipped plate or nicked gasket, or it
may wick out through the gel.)
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