cathode buffer for CN-PAGE - (Mar/15/2011 )

Now I moved to new lab, when I prepare cathode buffer( 50 mM Tricine and 15 mM Bis-Tris) for CN-PAGE, the pH is about 6. I never had this problem in my former lab. I can not adjust pH either with NaOH or Bis-Tris. Can anyone help me to check your solution pH. Thank you.

are you sure the pH meter and electrode are functioning properly?

how is the water that you use? how is it produced, stored? how old?

have you tried running the gel? if so, how does it look?