Hi! My lab is trying to get a relatively new tissue electrophoresis system up and running. We are using the protocol provided by the lab that originally published the technique in Nature of this year. It's a technique called CLARITY. We have followed the instructions and for some reason, when we begin the electrophoresis, the pH of the buffer begins to drop and continues to drop significantly over the course of the electrophoresis, which takes several days.
So my question is, what are we doing wrong? Is there some detail that was left out of the protocol or is it simply a matter of how we are preparing the solution? Let me give you some more information that might help you understand what we are dealing with.
The electrophoresis buffer is: 200mM boric acid, 4% SDS, made in 10 Liter batches and pH'd to 8.5 using sodium hydroxide
Electrophoresis is carried out at 40V for 5 days
Can anyone tell me why the pH of our solution is dropping under these conditions or what I might be able to do to fix it? Could I add more sodium hydroxide everyday to re-pH it?
I've attached the protocol in case that might help.
Is there electrochemistry occurring at the electrodes? Are there changes to the buffer solution composition in addition to the change in pH? What is your electrode material?