Gas chromatography on a self-associating component of a binary phase. Retention model by formal analogy with conductance of electrolytes in dilute solution

Elaborate treatment of retention in chemoselective chromatography--the retention increment approach and non-linear effects

The retention increment approach is described which quantifies the association equilibria of a selectand and a selector in complexation and inclusion chromatography. A thermodynamic treatment of enantioselectivity based on retention phenomena in chromatography including entropy/enthalpy compensation and the isoenantioselective temperature is advanced. Kinetic parameters of enantiomerization are discussed. Non-linear effects, both existent and elusive, are described and proposed, respectively. The enantioselectivity pertaining to catalysis vs. chromatography is compared and a unified nomenclature is proposed. Through an educational effort, this account is aimed at providing a deeper insight into chemoselective aspects of chromatography thereby stimulating further research of both established and speculative phenomena of the most intriguing manifestation of chemoselectivity, that is, of enantioselectivity.

Separation of enantiomers by gas chromatography

The separation of enantiomers by gas chromatography is performed on chiral stationary phases (CSPs) via hydrogen bonding, coordination and inclusion. Thus, typical chiral selectors are amino acid derivatives, terpene-derived metal coordination compounds and modified cyclodextrins. In Chirasil-type stationary phases the chiral selector is anchored to a polysiloxane backbone improving gas chromatographic performance. The present review article describes the state-of-the-art, scope and limitations, applications and mechanistic considerations at the advent of the millennium incorporating 16 figures and 168 references.