Why is electrophoresis carried out in buffer?

Question

Why is electrophoresis carried out in buffer?

Answer 1

Electrophoresis acidifies the solution on one side and alkalinizes it on the other side. If the run is long enough, the pH gradient will balance the difference in potential and migration will stop. Or at least this is what I was told - I don't get electricity much.

Answer 2

Most biological molecules have a charge that varies with pH.

So in order to get consisten results, you need to always do your electrophoresis under a set, consant pH.

So you need a buffer.

Edit:

I'm not convinced by special K's argument.

You only need an ionic solution to provide a conductive solution for running your gel in - you don't need a BUFFER as such (which is just there to keep the pH constant).

Answer 3

electrophoresis is the separation of charged dna, rna or proteins based on size.  the gel, either agarose or polyacrylamide are porous matrices that the proteins or nucleaic acids are pushed (Standard) or twisted through (Pulse Field Gel).

The buffer is necessary to complete the circuit of electron flow.  If you notice, there are 2 electrodes which drive a current from the top of the gel, where the proteins or nucleaic acids are loaded to the bottom.  Negatively charged proteins and nucleaic acids are pushed by this negative to positve (top to bottom) current flow.  without the running buffer in the gel box, the non-conductive agarose or polyacrylamide gel would do nothing.  The buffer completes the circuit so migration can occur.  it has nothing to do with pH except that you need to make your running buffer the right pH so you don't ruin the loaded samples or the gel, but that's a whole other story.