Liquid Chromatography of Benzoic Acid and Phthalic Acid on Ion-Exchange Resin

This is to report a study in which cation ion-exchange resin serves as the stationary phase for liquid chromatography of benzoic acid and phthalic acid and aqueous ethanol acts as the mobile phase. No ion. exchange phenomenon is involved. It is rather a solvent action on the polymer matrix for the organic solutes. It was found that the elution volumes depend on the pKa values of the acids; the higher the pKa value the more the retention volume.