Krebs buffer cloudy

[S.E.]

I am making up Krebs buffer for an isolated-perfused heart
preparation. The recipe for the buffer is as follows: NaCl 118mM,
NaHCO3 25mM, KCl 4.8mM, KH2PO4 1.2mM, MgSO4 1.2mM, Glucose 11mM
CaCl2(2H2O) 1.5mM and Sodium Pyruvate.

I was told to dissolve the chemicals in order and make sure that each
item is dissolved completely before I add the next chemical or else
the buffer will become cloudy. Unfortunately, even if I follow those
directions, the buffer will still become cloudy as soon as I add the
CaCl2 quite frequently.

Another researcher suggested to bubble the solution with 95%CO2/5%O2
for 5 minutes before adding the CaCl2, but that didn't solve the
problem.

I'd really like to be able to be able make to make this buffer
regularly without having to throw out the first 3 preparations because
they cloud up as soon as add the CaCl.....

Any suggestions?

Thanks is advance,
Stephanie

[Wolfgang Schechinger]

Maybe it's a pH problem that makes the Ca precipitate.

See http://www2.swmed.edu/rogersmr/perfusates.htm
http://www2.swmed.edu/rogersmr/perfusates.htm#Krebs-Henseleit%20(KH)%20Bicar
bonate%20Buffer
for details.

Just was googling for "krebs buffer cloudy" ...

HTH

Wo

>Any suggestions?=20
>
>Thanks is advance,=20
>Stephanie
>
>
Wolfgang Schechinger

---

[Wolfgang Schechinger]

pps you might dissolve the CaCl2 in a small amount od water and add it
dropwise while stirring well.

Wo
Wolfgang Schechinger

---

[Dr Engelbert Buxbaum]

S.E. wrote:

> I am making up Krebs buffer for an isolated-perfused heart
> preparation. The recipe for the buffer is as follows: NaCl 118mM,
> NaHCO3 25mM, KCl 4.8mM, KH2PO4 1.2mM, MgSO4 1.2mM, Glucose 11mM
> CaCl2(2H2O) 1.5mM and Sodium Pyruvate.

Dissolve the CaCl2 seperately in half the volume of water, than add to
the solution of the other chemicals under vigorous stirring. Ca3(PO4)2
is only slightly soluble in water, you must not exceed the solubility
product as it will not redissolve.