HPLC Analysis of Seven Anions on Heritage MA Mixed-Mode Column

Application description

Organic and inorganic acids are part of many formulations including pharmaceutical and nutraceuticals. These compounds are very often very polar and acidic, and either require expensive ion-chromatography or the use of ion-pairing reagents. Ion-pairing reagents are not compatible with mass spectrometry. Mixed-mode columns allow the utilization of the ion-pairing reagent attached to the surface of silica gel to retain these anionic compounds. The retention is provided by weak reverse-phase and by a medium or strong anion-exchange mechanism. The retention time is controlled by the amount of ACN, buffer pH and buffer concentration. Stronger and more hydrophobic acids will retain longer, and their elution can be effectively controlled by changing the ionization state at a different pH. This method is compatible with major detection techniques ( (ELSD, CAD, RI, UV and mass spec). This method can be used for the analysis of basic hydrophobic drugs and their acidic counter-ions in one run. Acidic hydrophobic drugs and related impurities can be analyzed on this mixed-mode HPLC column.