The chromatographic · properties of indole derivatives, mainly
biogenetically related to the plant growth hormone, indole-3-acetic
acid, were studied on Sephadex G-15. The eluents used were 70°/o
and 30°/o aqueous methanol, volatile ethylenediamine-acetate buffers
of pH 4.2 and 7.4, and distilleo water adjusted to pH 7.4. The
adsorption of indole derivatives to Sephadex could be preferentially
ascribed to the heterocyclic nucleus which is bound by rt complex
formation, as well as by hydrogen and hydrophobic bonding. The
presence of a side chain, if subject to the same type of binding
forces, results not only in stronger sorption but also in some exclusion
in accordance with molecular weight. Furthermore, because
of the carboxyl groups contained in Sephadex gels, positively charged
compounds are bound by ion exchange, whereas negatively
charged ones are acted upon by Donnan ion exclusion forces
