Separation of Phthalic Acids and Related Impurities on Zodiac HST RP Column

Phthalic acid, its isomers, and related by-products from the phthalic acid production process were effectively separated using the Zodiac HST RP mixed-mode column. This separation is achieved through a combination of reversed-phase and anion-exchange mechanisms. Neutral, hydrophobic compounds are primarily retained via the reversed-phase interaction, while phthalic acid and other acidic species are retained through both reversed-phase and anion-exchange modes. Resolution and selectivity can be finely tuned by adjusting the acetonitrile content, buffer concentration, and buffer pH. This method is well-suited for monitoring phthalic acid production and detecting related impurities and by-products.