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Hoefer DALT System
Troubleshooting
Amersham Biosciences
57
Power Supply detects current leak
•
Cracked or broken heat exchangers. Call your Amersham Biosciences
Service representative.
Spots are skewed or distorted
•
Gels run too fast-uneven migration.
•
Overlay the running gel with water-saturated
n
-butanol before
polymerization begins to avoid forming an uneven gel surface.
•
Uneven gel polymerization or gradient formation.
Heavy background after silver staining
•
Use reagents specified as electrophoresis purity.
•
Use only double-distilled water.
Unusually slow or fast run
•
Check for leaks; all plates and spacers must be clean, dry and free of
grease.
•
Make sure buffer level is not above the level of the upper spacer.
•
If the required pH of a solution is exceeded, do not back-titrate. Prepare
fresh buffer.
•
Check recipes, gel concentrations, and buffer dilutions. (For instance, do
not use Tris·HCl in place of Tris for the SDS electrophoresis buffer.)
•
Dispose of older acrylamide solutions and use only stock of the highest
quality.
•
Only use freshly deionized urea.
•
To increase or decrease the migration rate, adjust the voltage or current by
25–50%
Protein spots are diffuse or broader than usual
•
Use only high-quality acrylamide and bis.
•
Ensure that polymerization is complete.
•
Fully equilibrate IPG strips before second dimension.
•
Incomplete IPG focusing.
•
Make sure the IPG strip rests on the gel surface without gouging or
separating the gel.
Stained Sample Collects:
Near the buffer front
•
Molecules are not sufficiently restricted by the resolving gel pore size;
increase the %T.
•
Proteins may be degraded by endogenous proteases; use protease
inhibitors during sample separation.
•
Adjust the pH of 1.5 M Tris-Cl to pH 8.8. Samples migrate faster when
pH <8.8.
Near the top of the gel when the buffer front has reached the bottom
•
The gel pore size is too small. Decrease the %T of the resolving (or
stacking) gel.
•
Adjust the pH of 1.5 M Tris-Cl to pH 8.8. Samples migrate slower when
pH >8.8
At each end of the gel
•
The molecular weight range of the sample requires an acrylamide
concentration gradient to resolve the full range of proteins.
Содержание Hoefer DALT
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