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How to Make a Bis-Tris Transfer Buffer

The coupling of bis-tris is important in biochemistry due to its ability to act as a zwitterion, possessing a positive and negative ion on the molecule. It can serve as a buffer in the region of pH 7.6. It is added to the gels used in electrophoresis to help keep the molecules in solution and aids in the separation of the molecules. Transfer buffers remove molecules from gel plates of electrophoresis analysis and transfer them to membranes for western blotting. Each manufacturer of electrophoresis equipment reports slightly different recipes for making a transfer buffer, but the following is for the transfer buffer used with NuPAGE systems on non-reduced samples.

Things You'll Need

Bicine
Bis-tris
EDTA
250 ml beaker
Methanol
1,000 ml bottle
Ultrapure water

Instructions

- 1
  Prepare the ingredients for the buffer by weighing out the amounts of each component on an analytical balance. The three dry components for a transfer buffer is bicine, bis-tris and EDTA. Weight out 4.08 gm bicine, 5.23 gm of bis-tris and 0.29 gm of EDTA onto individual weighing papers.
- 2
  Add these components to a 250 ml beaker. Dissolve these components with 100 ml of methanol. Stir until the solids dissolve.
- 3
  Transfer the dissolved components to a 100 ml bottle and wash beaker with ultrapure water to ensure the transfer of all the components.
- 4
  Fill the remainder of the 1-liter volume with ultrapure water. Add the water in portions that allow sufficient mixing between each addition. Thoroughly mix the contents to achieve a uniform concentration.

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