Sample loading buffer turning yellow. - (Jun/23/2010 )

I added sample loading buffer (Bromophenol blue) to my sample and after boiling for 5 min, it turned yellow. Does anyone know the explanation behind this?

Thanks.

Aravin on Jun 23 2010, 10:48 PM said:

Actually, BPB is a pH indicator turning yellow at acidic pH; so, your sample contains some protons which were not buffered by the sample buffer. Was it blue before boiling? Why so long boiling?

Inmost sun on Jun 24 2010, 03:59 PM said:

i second tat.. ur sample had acidic pH!!!
once u load it and the gel starts running it will again turn blue cause of the pH of the lamelli buffer!!!

Stumbled upon this when googling for my own stuff.

31. Sample preparation yellow in colour

a) Solution acidic: add NaOH until the solution turn blue.

Too little bromophenol blue in sample buffer.


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