Martin Humphries

Protocols - Colloidal Coomassie Blue Stain

Written by Guillaume Jacquemet

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Coomassie stained gel

- Stain Preparation:

In a large beaker add the ingredient in the order listed below

  1. Distilled H20 about 650 ml
  2. Ammonium Sulfate, 100g (final concentration 10%)
  3. Make sure the Ammonium Sulfate is dissolved before adding the Coomassie G-250 solution to a final of 0.1%.
  4. Coomassie G-250 (Sigma: B0770), 20 ml of 5% (w/v) solution in H20
  5. Ortho-Phosphoric Acid, 30 ml
  6. Ethanol, 200 ml
  7. Bring final volume up to 1L with H20

- Procedure:

  1. After SDS PAGE rinse gel twice with 100 ml distilled H20 (3 minutes each wash)
  2. Add Coomassie Blue working solution to gel and stain for at least 2 hours (for convenience this can be left to proceed overnight)

Bands should be visible without de-staining but you can de-stain with H20

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