ABSTRACT
This chapter discusses some basic physical principles of chromatographic separations; adsorption chromatography which is founded on the energetic reversible binding of gas, liquid or solid at a solid surface; the partition or liquid-liquid chromatography is another process based on the difference of partition constant of the solutes to analyze between aqueous and water-immiscible phases; the ion-exchange applies to a stationary phase possessing the capacity to exchange some of its ions with those of the mobile phase. Also, it is possible to use the formation of ion pairs which permits the separation of ions or ionic compounds. They are some neutral entities that are extractable in a low polar organic medium. Size-exclusion chromatography is based on the selective retention of samples according to the size of their molecules. They are included or excluded from the porous spherical beads of the stationary phase filled by the solvent. The description of mechanisms of retention, supports, stationary and mobile phases and the impact of pH, temperature and ionic strength on the equilibrium are investigated for each type. Some applications illustrate the chapter.
