HPLC Analysis of Benzenesulfonic and p-Toluenesulfonic Acids on Amaze TR Mixed-Mode Column

Application description

Benzenesulfonic and toluenesulfonic acids are common organic acids used as counter-ions in pharmaceutical industry. Both acids are hydrophilic in nature with strong acidic properties. When traditional RP columns are used, poor retention and peak shape are observed due to non-specific secondary interactions. We developed a robust mixed-mode approach for the separation of benzenesulfonic acid and p-toluenesulfonic acid on the Amaze TR reversed-phase anion- and cation-exchange column. Both acids are retained by a weak reversed-phase mechanism and strong anion-exchange mechanism. The elution of these compounds is controlled by the amount of pH of the buffer, concentration of ions and the amount of acetonitrile in the mobile phase. The method is reproducible and effective with a good retention control and peak shape. It is compatible with major detection techniques including mass spectrometry (MS), Evaporative Light Scattering Detection(ELSD), ultraviolet detection and refractive index detection.