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Bradford Stock Solution Preparation

This solution is mainly used to determine the concentration of proteins in solution.

Bradford Stock Solution

  • This solution is mainly used to determine the concentration of proteins in solution.
  • The principle of detection is based on the formation of a complex between the dye, Brilliant Blue G, and proteins in solution.
  • The protein dye complex causes a shift in the absorption maximum of the dye from 465 to 595 nm. The amount of absorption is proportional to the protein present.
  • The Bradford Reagent requires no dilution and is suitable for micro, multiwell plate, and standard assays. 
  • This solution also compatible with reducing agents which are often used to stabilize proteins in solution.
  • This solution is consist of t consists of Brilliant Blue G in phosphoric acid and methanol.
  • Bradford Stock Solution is stable at 2–8 °C in an unopened container for at least 1 year.

Preparation of Bradford Stock Solution

To prepare 1L of Bradford Stock Solution, the following components are required;

Ethanol (95%) (mw: 46.07 g/mol)333 mL31.67 %
Phosphoric acid (88%) (mw: 58.4 g/mol)667 mL58.67 %
Coomassie Brilliant Blue (mw: 825.97 g/mol)1.16 g1.41 M


  1. Prepare 0 mL of distilled water in a suitable container.
  2. Add 333 mL of Ethanol (95%) to the solution.
  3. Add 667 mL of Phosphoric acid (88%) to the solution.
  4. Add 1.16 g of Coomassie Brilliant Blue to the solution.
  5. Add distilled water until volume is 1 L.




MN Editors. (May 4, 2021).Bradford Stock Solution Preparation. Retrieved from https://microbiologynote.com/bradford-stock-solution-preparation/


MN Editors. "Bradford Stock Solution Preparation." Microbiology Note, Microbiologynote.com, May 4, 2021.


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