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Specialty Chemistry Forums => Biochemistry and Chemical Biology Forum => Topic started by: ConfusedBiologist on September 30, 2014, 04:57:52 AM

Title: Matching ionic stregnths of Sodium Succinate Buffer and Ammonium Acetate
Post by: ConfusedBiologist on September 30, 2014, 04:57:52 AM

Hi,

I'm a biotechnologist and I've been asked to match the ionic strength of:

20mM Sodium Succinate
125mM Arginine
pH6

with Ammonium Acetate, pH6.

I know I need to calculate the amount of dissociation to obtain the concentration of ions in the buffer before using the ionic strength calculation. However, I have never used these before so was looking for some advice!

Thanks very much in advance!

Title: Re: Matching ionic stregnths of Sodium Succinate Buffer and Ammonium Acetate
Post by: Borek on October 02, 2014, 03:02:10 PM

If the pH is forced on the system calculations of concentrations of all forms is rather easy - see here: http://www.chembuddy.com/?left=pH-calculation&right=pH-polyprotic-acid-base

Equations 9.11 to 9.13 (or similar forms for acids other than diprotic, there is an obvious symmetry in these equations which make the generalization easy) can be used to find concentrations of all forms present in the solution.