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sample buffer pH - its effect?? (Dec/14/2009 )

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biolabwork on Feb 15 2010, 03:05 PM said:

What could be the reason for color change of Lammli buffer? I was in Blue color whne prepared. Now changed to light red!

bromphenol blue will turn yellow at low pH, maybe there is a second dye in the buffer (phenol red?).

if you used coomassie brilliant blue g-250 as a tracking dye (why?) it will turn reddish-brown at low pH.


I used tuny bit bromophenol blue . Nothing else as dye.


how old is the buffer?

could something have contaminated it?

the color may be in transition as pH is dropping (probably due to adsorption of co2 from the air).

check the pH.

better yet, discard the buffer and make fresh.

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