Primesep® mixed-mode stationary phases provide two functional groups for interaction with analytes.
One is a very hydrophobic alkyl chain; another is a very hydrophilic acidic residue (Primesep A, Primesep 100, Primesep 200) or a protonated base (Primesep B).
As these two functional groups substantially differ in polarity, multiple separation modes can be performed on the same column.
Neutral compounds can be resolved in reverse, normal, or polar organic mode. Charged molecules can be resolved in reverse, normal, polar organic, ion-exchange, or ion-exclusion modes. Ionizable molecules usually require a combination of two or more modes.
Selection of the separation mode is governed by the type of the mobile phase chosen for a particular separation.