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Change in elution time with protein concentration

Posted: Fri Feb 26, 2010 11:15 am
by DaveM
Good morning,

I saw something today which I have not seen before and haven't heard of. Perhaps someone with more experience can advise?

I am injecting an intact protein on a C3 column, 300A pore (for analysis only, hence not HIC or ion exchange), in a gradient of acetonitrile in 0.1% TFA. Injecting the protein from its storage buffer (low buffer strength, 100mM sodium chloride) gives a reproducible, symmetrical peak. However, diluting the protein by 10x in the same buffer before injection of the same volume gives a peak of a tenth of the area, but the elution time is quicker.

Is this normal?

With thanks,

D.