Effect of the type and concentration of mobile phase additives on the separation of salbutamol sulfate enantiomers in supercritical fluid chromatography

The influence of a set of additives of various nature on the separation of salbutamol sulfate enantiomers by supercritical fluid chromatography on the stationary phase based on amylose tris(3-chloro-5-methylphenylcarbamate) is considered. The application of water and acidic additives does not lead to enantioseparation. The use of hexafluoroisopropyl alcohol as an additive allows separation to occur but leads to a strong distortion of the chromatographic peaks. The application of basic additives such as isopropylamine or ammonia provides a stable separation with high selectivity and resolution as well as with the symmetrical peak shape. The selectivity coefficient is surprisingly almost independent of the amine modifier concentration in the mobile phase.