The stationary phase in the ALKION column is a rigid, non-porous polymeric phase that is surface sulfonated.
The two modes of separation are ion-exchange and moderate partitioning. The low capacity of the ion-exchange resin makes it an ideal phase for the separation of strongly basic and positively charged compounds. The reversed-phase character allows for discrimination between closely related species.
If the cations being separated are positive by virtue of being basic, then there are two options to effect
separation: titration (increasing the pH), or competitive ion-exchange. As the eluant pH increases, the bases become neutral and so are released in the reverse order of their respective pKb’s. Positive compounds are eluted
by the continuous flow of cations or by increasing cation concentration over time.
Partitioning is accomplised by the use of water miscible organic solvents. In this instance, the optimum choice is i-Propanol (iPA).
Neutral and weakly basic components of the sample matrix are not ALKION Column and Eluant System retained and so elute early in the chromatogram, causing little or no interference with the separation of strongly basic and cationic analytes. This means that minimal sample cleanup is required before analysis; usually centrifugation and filtration are sufficient.
The ALKION eluant system consists of four phases: a buffer (K01), a titrant (K02), an ionic strength adjuster (K03) and a solvent, iPA. The K01/ K02 ratio controls the pH, the % K03 controls the eluant normality and the iPA mediates the partitioning.