Dual Gel Caster, 1 or 2 gels

Acrylamide or bis acrylamide contains acrylic acid, a breakdown product

Use reagents specified as electrophoresis grade in purity.

Water is impure.

Use only double-distilled water.

The pH of the stacking gel or running buffer is incorrect

Check buffer stocks and casting recipe.

Too high sodium or potassium concentration.

Avoid using solutions with a high sodium or potassium concentration

Issues with the acrylamide solution

1. Check the expire date of the acrylamide solution
2. Use only the highest grade of acrylamide

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For best results, allow a stacking gel height of 2.5 times the height of the sample in the well

Poor stacking

Pour a taller stacking gel. (For best results, allow a stacking-gel height of 2.5 times the height of the sample in the well.)

Reagent quality

Dispose of outdated acrylamide solutions and use only the highest grade of acrylamide

Sample preparation

When preparing samples, avoid using solutions with high salt concentrations

Too much bisacrylamide.

Crosslinker should be at 2.6 %C for standard SDS (Sodium dodecyl sulfate) gels where:

%C = (g bis x 100)/(g monomer + g bis)

Dirty plates e.g. fingerprints

Soak plates in a strong laboratory detergent and rinse well in distilled water. Please use gloves.

Plates are scratched

Replace glass plates. To some extent the effect of scratches can be counteracted by treating plates with silanizing reagent such as Repel-Silane.

Plates were stored with, or soaked together with, plates that were pre-treated with Bind-Silane.

Always segregate Bind-Silanized plates. Bind-Silanized plates can "contaminate" untreated plates if placed in contact, or soaked together. Glass plates can be re-used after scraping off the polyacrylamide gel and thoroughly washing the glass plates with strong sodium hydroxide solution.

Too much catalyst: gel polymerized in < 10 min

Reduce both APS (Ammonium persulphate) and TEMED by 25%.

Not enough catalyst: gel polymerized in > 50 min

Increase both APS (Ammonium persulphate) and TEMED by 50%

Solutions not mixed

Mix thoroughly after adding TEMED

Poor chemicals

1. Use only recent stock of the highest quality reagents.

2. If the dry ammonium persulphate does not crackle when added to water, replace with fresh stock.

3. Increase TEMED or APS (Ammonium persulphate) concentration, or both.

Solutions with extreme pH values (especially acidic) may not polymerize.

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Oxygen is present

Remove oxygen from the gel environment: Degas the monomer solution 5 to 10 minutes before pouring and then overlay the gel surface with water-saturated n-butanol.

Gel solution has too low temperature

Adjust the gel solution temperature to a minimum of 20 °C, especially for low %T (Total acrylamide concentration) gels.

Too low concentration of TEMED or APS (Ammonium persulphate)

Increase TEMED or APS concentration, or both

Not enough crosslinker

Crosslinker should be at 2.6 %C for standard SDS (Sodium dodecyl sulfate) gels where:

%C = (g bis x 100)/(g monomer + g bis)

Too much bisacrylamide

Check concentrations of solutions