Researches on sulphanilamide, para‐amino‐benzoic acid and their derivatives. IV: The behaviour of sulphanilamide, p‐aminobenzoic acid and of their derivatives with respect to the mercury/solution interface (polarographic investigations) and to lecithin and protein monolayers

Abstract

Sulphanilamide, p‐aminobenzoic acid and a number of their derivatives are studied polarographically in order to ascertain whether or not it is probable that p‐aminobenzoic acid functions in a redox system, and to compare their affinities for the rather apolar mercury/solution boundary. The latter serves to a certain extent as a model for a lipophilic membrane of a type within which London‐van der Waals' forces predominantly determine the degree of interaction. In this way very typical differences come to the fore which generally parallel those obtained in the investigations of U.V. absorption spectra and electrochemical properties, as well as the activity of the compounds in vivo. For p‐aminobenzoic acid it may be concluded that a direct function in a redox system is very improbable. In addition mono‐layers of lipoid or protein character are used as models for membranes in which other types of forces than those considered above play a rōle.