3 replies to this topic

[Aravin]

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.

[Inmost sun]

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

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.

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?

Edited by Inmost sun, 24 June 2010 - 02:31 AM.

[Prep!]

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

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

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.

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?

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!!!

Edited by Prep!, 24 June 2010 - 08:42 PM.

[zienpiggie]

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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