Data from literature, interpreted in terms of phase transitions in the adsorption layer are analyzed with a recently developed thermodynamic model that considers the formation of small aggregates or larger clusters at the interface. The interfacial tension isotherms for perfluorinated (FC12OH and FC10OH) and aliphatic (C20OH and C18OH) alcohols at the water/hexane interface can be satisfactorily explained by this thermodynamic model. It is also shown that an interfacial phase transition would require a change in the interfacial tension isotherm opposite to that observed experimentally.