[Contribution on standardisation of the colloidal iron binding reaction (author's transl)]

The iron binding reaction provides inconstant results with respect to the number of electron dense particles bound to cell surfaces if acetic acid has been used for the production of the colloid and for washing procedures in the course of iron binding. In the present paper it is shown that the dilution of colloidal iron hydroxide by adding acetic acid changes the size distribution of the colloidal particles, resulting in a marked decrease of iron binding. For that reason, a standard method is proposed in which hydrochloric acid is used instead of acetic acid. By this modification more reproducible results are gained with regard to the above mentioned quantitative aspects.