ABSTRACT
This chapter deals with an explanation of hydrophobic interaction in molecular and thermodynamical terms and discusses the use of both charged and uncharged amphiphilic gels. Characteristic of ion-exchange chromatography is, therefore, that the adsorption decreases upon an increase in the temperature or ionic strength of the eluting buffer. For hydrophobic-interaction chromatography the situation is reversed and the interaction increases with the temperature and ionic strength. The term "hydrophobic-interaction chromatography" is thus appropriate when the latter gels are used as bed materials. If the substance of interest elutes in the buffer together with much contaminating material a similar experiment should be performed on a gel of the higher hydrophobicity, for instance decyl-Sepharose. On the other hand, if the material to be purified cannot be desorbed a gel bed with a ligand of the lower hydrophobicity should be tried, such as pentyl-Sepharose.
