[stevier]

Hi

In my work in a serology lab we use a Buffer which is supposed to be PH7.2

It comes in powder form and we dissolve and make it up to 1 litre in deionised water.

We use a calibrated PH meter to measure its PH.

Occasionally it will be measured at 7.3, 7.1 etc

My question is, what formula can I use to determine how much acid, or alkali to add to bring it from a measured PH, eg 7.3 back down to 7.2?

[Arkcon]

You could use a formula, but because of various ways the calculations are idealized and the sample isn't, you'd be better off just adding acid or base dropwise.