Change of pH of Phosphate buffer with Imidazole
Posted 03 August 2010 - 05:41 AM
I am preparing a set of phosphate buffers for my protein purification. I have the stock phosphate buffer 500 mM pH 7.8. I dilute to make 20 mM buffer. However, If I add NaCl (500 mM) and Imidazole (20, 50 and 500 mM) the pH changes considerably. In that case, how to make the final pH to 7.8? Can I add HCl or one of the phosphate solutions to adjust the pH? Will it not affect the ionic strength of the final buffer? I want all the buffers at same pH and ionic strength as I am going to use them for gradient wash/elution.
Many thanks in advance.
Posted 03 August 2010 - 06:36 AM
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