Control of Cation Exchange Properties by pH of Primesep C Column

Primesep C demonstrates the control of ion-exchange properties of Primesep columns. The peak order of caffeine and benzylamine in a mixture of caffeine, benzylamine, and phenol reverses when the mobile phase modifier is changed from ammonium acetate to trifluoroacetic acid. Control of the separation is possible even with mass spec (LC/MS) compatible mobile phases of water, acetonitrile (MeCN, ACN) and ammonium acetate or trifluoroacetic acid (TFA).