Meg wrote:
> Dear All,
>
> I want to prepare 25 mM sodium acetate buffer pH 4.5. can anyone give the
> exact composition of how to prepare it. we prepare it using sodium acetate
> and acetic acid combination. i am not able to arrive at the calculatation
> correctly, so if anyone can explain me with the above buffer how to
> calculate. and what sodium acetate [Anhydrous / trihydrate] and acetic acid
> [glacial/ plain] to use.
>
> thanks n regards
>
> Meg goyal,
> M.SC Biotechnology [Research]
> Institute of science,
> Fort
> Mumbai, INDIA
>
If you want to get the pH exactly right, the only proper way to do this
is to make a solution of 25 mM acetic acid in water (leaving out about
20% of the water temporarily), then titrate with NaOH until you reach a
pH of 4.50. Then make up to the final volume with water and mix. You can
get the proportions approximately right by using the
Henderson-Hasselbalch equation, but in practice the pH may not come out
exactly right.
--
------------------------------------------------------------------------
Roger S. Rowlett
Professor
Colgate University Presidential Scholar
Department of Chemistry
Colgate University
13 Oak Drive
Hamilton, NY 13346
tel: (315)-228-7245
ofc: (315)-228-7395
fax: (315)-228-7935
email: [log in to unmask]
|