[Manie28]

Hi,

I want to prepare a colloid solution with following paramters:

Colloid-Conc: 0,05 g/l
pH = 4
Ionic strength : 0,01 M (NaCl)
Eu ³⁺ conc: 10^-5 M
Volume: 50 ml

After preparing 50 ml solution with colloid conc. of 0,05 g/l, Ionic strength of 0,01 M (NaCl), Eu conc of 10^-5 M  I pipet 0,01 M NaOH into 5 ml of this solution to adjust the pH to 4.

The problem is, that I have to add 300 µl of 0,01 M NaOH to adjust the pH to 4 in 5 ml solution. This leads to a fault of > 5 %.

Thus, my question is, how can I adjust the pH with smaller deviations?

I could use 0,1 M NaOH, but the only the deviation in Volume would be smaller, the deviation of Ionic strength would be the same...


Thanks in advance for your *delete me*

[Borek]

Search forums, I have a gut feeling that this subject was already discussed (ie Eu solution of similar parameters).