VWR Peqlab PerfectBlue Mini S Instruction Manual page 12

Instruction Manual PerfectBlue Horizontal Mini Gel Systems
TM
Problem: Samples do not band sharply.
Gels should be allowed to solidify completely before running. Standard agarose should solidify in about
30 minutes. If low melting point agarose is used, it may be necessary to completely solidify gels at a
cooler temperature in the refrigerator or cold room. Gels should be submerged in 3 - 5 mm of buffer to
prevent the gel from drying out, but excess buffer (> 5 mm) can cause decreased DNA mobility and
band distortion. Perhaps too much nucleic acid was applied to the wells potentially leading to
smearing of the bands.
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Problem: Samples are remaining in the wells, running 'backwards' or diffusing out of the gel.
Check that a complete power circuit is achieved between the unit and the power supply. Platinum wire
and banana plugs should be intact. To test, simply fill the unit with running buffer and attach to the
power supply without a gel or gel tray in the unit. The platinum wires on both sides of the unit should
produce small bubbles as the current passes through. If a complete circuit does not exist there will be
little to no bubbles. If samples appear to run backwards through the gel or there are no bands visible,
check to be sure that the gel tray was placed in the electrophoresis chamber in the proper orientation. If
the orientation or polarity is reversed, the samples will run backwards or migrate off the gel. The tray
should be placed in the chamber with the comb at the edge of the tray closest to the cathode side (black)
of the chamber.
Problem: When the comb is removed from the gel the sample well is ripped and damaged.
Always make sure to allow the gel to solidify completely and note that the gel should be submerged by
running buffer before moving the tray, unit, or removing the comb. To avoid damage to the sample
wells, gently rock the comb back and forth lightly to loosen and then slowly pull the comb straight up out
of the gel tray. This rocking helps to avoid suction as the comb is removed.
Problem: The gel seems to run slower under the usual running conditions.
The volume of running buffer used to submerge the gel should only be between 3 - 5 mm over the gel
surface. Gel should be completely submerged to avoid the gel from drying out and to assure that a uni-
form electrical field can be generated. However, if excessive running buffer is used, the current flow
through the gel and the migration of the DNA is decreased.
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