ISO 4314:1977

Surface active agents — Determination of free alkalinity or free acidity — Titrimetric method

The determination is carried out in the following way: Titration of an ethanolic or propanolic solution of the product with a standard volumetric potassium hydroxide or hydrochloric acid or sulphuric acid solution whichever is appropriate, in the presence of phenolphthalein as indicator.