Effect of Acid on Separation of Xanthines

The Zodiac HST B column enables effective separation of xanthines such as theobromine, dimethylxanthine, and theophylline through a combination of reversed-phase and ion-exchange mechanisms. Its anion-exchange properties facilitate retention of hydrophilic xanthines, while reversed-phase interactions retain more hydrophobic compounds. The separation is performed using a mobile phase composed of water, acetonitrile (MeCN, ACN), and an acid modifier such as trifluoroacetic acid (TFA), perchloric acid (HClO₄), or sulfuric acid (H₂SO₄), with UV detection.