Bio-Rad Sub-Cell® Model 192 Cell - Manual (Page 22)

Section 5
Troubleshooting
Symptoms Probable Causes Solutions
Slanted lanes (bands)
Curved line or distortion of
lanes (bands)
Differential relative mobilities
Curved bands, smiles
Ragged bands
Band smearing and streaking
Bands sharp but too few bands
seem
High MW bands sharp/Low MW
bands smeared
Gels crack
• Gel not fully solidified.
• Comb warped or at an angle.
• Bubbles in sample wells.
• Sample spilled out of wells.
• Unit not leveled.
• Gel floated or slid off tray.
• Sample overload.
• Temperature or pH buffer
gradients
• Sample density incorrect.
• Sample well deformed.
• Excessive power or heating.
• Agarose has improper endos-
mosis (-m
r
).
• Salt concentration in sample
too high.
• Excessive power and heating.
• Sample spilled out of well.
• Incomplete digest, nuclease
contamination, bad enzyme.
• Sample wells cast through the
gel. Sample leaks along bot-
tom of running surface.
• Sample overload.
• Too high gel percentage.
• Incomplete digest.
• Gel percentage too low.
• Too high voltage gradient
especially with low melting
temperature agarose or low gel
strength gels.
• Let gel solidify for at least
30-60 minutes.
• Check alignment of comb.
• Remove bubbles prior to
electrophoresis.
• Samples should have proper
density. Apply carefully.
• Level unit. Place on steady
work bench.
• Recirculate at a rate of
300-500 ml/min.
• Reduce the amount of sample
loaded.
• Reduce load.
• Add more buffer.
• Recirculate buffer.
• See sample application
instructions.
• Carefully remove comb, espe-
cially from soft gels. Be sure
gel has solidified. Cooling soft
gels aids in comb removal.
Add buffer to help lubricate
removal of the comb.
• Reduce voltage. See elec-
trophoresis instructions.
• Consult Bio-Rad about
agarose.
• Reduce salt concentration to
≤
0.1 M.
• Reduce voltage. See elec-
trophoresis instructions
• Take care in applying sample.
Increase gel thickness for large
sample volumes.
• Heat sample. Check enzyme
activity. Digest sample further.
• Comb should be placed 1 to
2 mm above the base of the run-
ning surface. Add buffer to help
lubricate removal of the comb.
• Dilute sample.
• Lower gel percentage.
• Check enzyme activity, digest
further.
• Increase gel percentage.
• Switch to polyacrylamide.
• Reduce voltage. Run gel at
lower temperature.
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