Bonded reverse phase ion exchange columns for the liquid chromatographic separations of neutral and ionic organic compounds.

Octadecylsilane was chemically bonded in situ on cation and anion exchange packings. The columns were tested for the liquid chromatographic separations of neutral and charged organic solutes which included nucleotides, polynuclear aromatic hydrocarbons, amines, carboxylic acids, and organometallic compounds. While some separations were effected predominantly by either the ion exchange sites or the reverse phase moieties, most separations appeared to be the combined effects of both stationary phases. The reverse phase partitioning, apparently induced by the solvophobic interaction, can make the elution volume and order of a charged solute significantly different from that found in a conventional ion exchange column. The mixed mode of ion exchange and reverse phase solvophobic interactions are illustrated.