Thin-layer reversed-phase ion-pair chromatography of some sulphonamides.

The retention behaviour of 15 sulphonamides was investigated by thin-layer reversed-phase ion-pair chromatography (RP-IPC). Optimization of the retention and selectivity of these compounds was carried out by changing the pH, the concentration of the ion-pairing counter-ion and the concentration of the organic solvent in the aqueous mobile phase. The effects of various cationic and anionic pairing reagents in the mobile phase and the stationary phase were investigated. The use of stepwise gradient elution improved the spot shape and the selectivity of the separation.