[jeffmoonchop]

Hi I'm working on process development for a formulation where to make the formulation ethanol has to be used as well as an acetate buffer. When the formulation is made the pH is 6.5 and the concentration of ethanol is around 17%.

After the formulation is made I remove the ethanol by dialysis because it is harmful on standing. I'm doing some experiments to find out the actual harmful effect of ethanol and to do that I need to make the same buffer mixture as the formulation is made it but without ethanol and at the same pH.

I've been told that ethanol may give a false value to the pH, so if I make the same solution without ethanol to pH 6.5, the 'real' pH will actually be different? Is this true and how can I correct the non-ethanol buffer according to the magnitude the ethanol changes the pH?

[Borek]

Technically pH is something defined for water, not for water/ethanol mixtures, so I would be ready for irreproducibility.