Adsorption properties of synthetic piceatannol

The adsorption isotherms of synthetic piceatannol (trans-3,5,3′,4′-tetrahydroxystilbene) from n-hexane-ethyl acetate at nanodispersed silicon, titanium, and aluminum oxides were measured under static conditions. The adsorption properties of piceatannol and other hydroxystilbenes were compared with those of polyphenols. It was found that piceatannol adsorbs at titanium oxide better than at alumina and silica and almost as well as phloroglucinol adsorbs at these oxides. The adsorption isotherms can be satisfactorily approximated by the Freundlich equation for the model of localized adsorption at energetically heterogeneous sites. The influence of the nature and concentration of the polar components of a binary organic solvent on the adsorption of piceatannol at silica gel was studied by normal-phase chromatography and UV spectroscopy. The dependences of the retention factors of piceatannol and other hydroxystilbenes on the solvent composition were described by a simple analytical equation. The optimum composition of the mobile phase for separation of piceatannol and other stilbenoids was found.