Strong cation exchange column allow for symmetrical peak shape and increased sample loading in the separation of basic compounds

Strong cation exchange (SCX) mode, an alternative to reversed-phase (RP) mode, was described in this paper to obtain symmetrical peak shape and high sample loading for the separation of basic compounds. The retention mechanisms on SCX modified silica sorbents have been demonstrated including electrostatic and hydrophobic interactions. The effects of eluent ionic strength, apparent pH on retention were investigated and the cation-exchange capacity was also characterized. Good efficiency (>56,000 plate m−1) and excellent peak shape (Tf < 1.2) for various basic probes were obtained on the SCX column. Furthermore, good peak shapes and separation can be maintained under high concentration injections, indicating good potential in preparative use. These results were also compared with those obtained on two conventional RP stationary phases. The overall results demonstrated that SCX stationary phases can be used as alternatives to RP stationary phases in the separation of basic compounds, especially in the purification of basic compounds.

► Symmetric peaks can be obtained even with high amount of bases injected. ► Significant peak tailing or broadening is negative on SCX column. ► Good column efficiency can be obtained on SCX column.