Separation of primary and secondary amines as their sulfonamide derivatives by reversed-phase high-performance liquid chromatography

A series of simple and low-molecular-mass aliphatic amines were derivatized with 8-quinolinesulfonyl chloride. Mixtures of the respective substituted sulfonamides were separated by reversed-phase high-performance liquid chromatography (RP-HPLC) and the sulfonamides were found to be highly sensitive to ultraviolet detection. This pre-column derivatization facilitated good separation of eleven amines with the separation factors, alpha, better than 1.10 and the separation time within 20 min. The optimization of separation was conducted and investigated on intermediate polarity (cyano) and apolar (hexyl) stationary phases. A linear relationship was observed between the retention and the incremental carbon number of sulfonamides formed and thus making possible the retention prediction of the amine derivatives on RP-HPLC columns.