Church's Buffer for Northern and Southern Blot Hybridization

Church's buffer is commonly used for Northern and Southern blot hybridization.

Church's buffer composition

ComponentTarget concentration
BSA1% (w/v)
EDTA1 mM
Sodium phosphate (pH 7.2)0.5 M
SDS7% (w/v)

How to prepare Church's buffer

  1. Add approximately 800 mL of ultrapure or deionized water to a suitable vessel.
  2. Prepare a 0.5 M sodium phosphate system at pH 7.2 using both monobasic and dibasic sodium phosphate.
  3. Add BSA to 1% (w/v), EDTA to 1 mM, and SDS to 7% (w/v).
  4. Stir until all components are completely dissolved and the solution is uniform.
  5. Adjust the final volume with water as needed.
  6. Filter sterilize if required for the intended application.

Note: Use both monobasic and dibasic sodium phosphate to prepare the 0.5 M sodium phosphate component at pH 7.2.

Note: Adding SDS from an existing stock solution is often easier and faster than weighing SDS powder directly.

Reference: PNAS 81:1991-1995, April 1984.