Exact buffer calculations

Cecil Jack cjack at pipeline.com
Wed Jun 9 13:13:25 EST 1999


"Basic Biochemical Laboratory Procedures and Computing", R. Cecil Jack,
Oxford University Press, 1995, may have some of the information you seek.

Cecil

In article <7ir1n1$hba$1 at nnrp1.deja.com>, klaus_frommerr at my-deja.com wrote:

>Dear scientists,
>
>Can anyone of you recommend me relevant literature and/or software
>programs (DOS/Win) for use with exact buffer calculations? (The software
>could be an Excel, Mathcad or Mathematica document too, it needs not be
>an external program.)
>At first glance, it might seem that something like this is not necessary
>because normal buffer calculations are very easy indeed. But:
>My biochemical lab work requires me to prepare buffer solutions with
>very exact pH values (and sometimes I have to control ionic strength as
>well, so titration is not the method fit best for this purpose).
>However, pKa values of buffers (=> pH) depend on several factors that
>are usually neglected, which is justified in many cases as the effects
>are minimal. But in my case I have to take these factors into account to
>be able to prepare buffers with sufficient precision for my needs.
>pKa values depend on
>1) activity factors
>2) ionic strength
>3) pH
>4) temperature
>and the normal values you can find in (bio-)chemical data collections
>are standard values. What I am now looking for are formulae which
>consider these factors and allow precise calculation of buffer
>solutions. Common literature in physical (bio-)chemistry did not give me
>the required information, at least I haven't been able to find it.
>I am also looking for formulae treating ampholytes and mixed buffers.
>I can well imagine that some of the calculations are fussy or tedious
>work, that was why I was also asking for software doing such
>calculations.
>I hope you can help me with my concerns. Of course, any comments are
>welcome as well.
>Thanks in advance for any advice!
>
>Best regards
>Klaus Frommer
>kf-mailbox at usa.net
>
>
>Sent via Deja.com http://www.deja.com/
>Share what you know. Learn what you don't.



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