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SIELC Technologies provides several different columns with negatively charged functional groups due to the embedded anionic ion-paring reagent. Primesep A is the strongest acidic column, while Primesep C is the weakest acidic column. The Primesep 100 and Primesep 200 columns are in between. Difference in the functional group acidity allows selecting the most appropriate column for a particular set of basic compounds that differ in their pKa value.
The embedded acidic functional group can be in an ionized form, or in a non-ionized form, depending on the pH of the mobile phase. In order to get retention by ion-exchange mechanism on Primesep® columns, the pH of the mobile phase should be selected close to, or above, the transition value of embedded acidic groups. Below the transition pH value, the column behaves as a regular reverse-phase column with an embedded non-ionized polar group.
The column name corresponds to pH value of the mobile phase where acid residue on the column switches from ionize form to neutral one.
| Cation-exchange Column Type |
About 50% of embedded acidic groups ionized at transition pH value |
Separates basic compounds |
| Primesep 500 |
pH = 5.0 |
strong bases, dibases, polybases |
| Primesep C |
pH = 3.5 |
strong bases, dibases |
| Primesep 200 |
pH = 2 |
strong bases, dibases |
| Primesep P |
pH = 1 |
weak, medium aromatic bases |
| Primesep 100 |
pH = 1 |
weak, medium bases, AA, metals |
| Primesep A |
Ionized in all working pH |
weak bases, AA, metals |
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