Separation of Sodium, Potassium, Lithium, and Ammonium in Mixed-Mode HPLC

Inorganic cations and ammonia are usually analyzed by ion-exchange chromatography with a conductivity detector. Mixed-mode chromatography achieves the same goal with an ELSD detector. In addition to retaining ions, mixed-mode column can retain hydrophobic molecules also, making it possible to analyze a wide variety of ionic and non-ionic compounds in one run. In this method sodium, potassium, and lithium ions were separated along with ammonium ions on a Primesep 100 column. Detection technique is ELSD.