On physical meaning of van't Hoff equation and its applicability in chromatography.

The van't Hoff equation is a widely used tool to study adsorption thermodynamics in chromatography. Recent experimental data and some theoretical arguments questioned the accuracy of thermodynamic characteristics determined by using this equation. The present report addresses these concerns and shows that if certain requirements are satisfied, the van't Hoff analysis provide reliable results.

Chiral zwitterionic stationary phases based on Cinchona alkaloids and dipeptides: Application in chiral separation of dipeptides under reversed phase conditions.

Chromatographic behavior of novel chiral stationary phases with bonded selectors based on Cinchona alkaloids modified with dipeptides was studied using dipeptides as probe molecules. Buffer-free and salt containing hydro-organic solutions were used as the mobile phases. The selectors exhibit pseudoenantiomeric behavior with respect to the L/D or LL/DD enantiomers and do not behave so with respect to the LD/DL enantiomers.

Chiral zwitterionic stationary phases based on Cinchona alkaloids and dipeptides - design, synthesis and application in chiral separation.

Chiral resolution of polar organic compounds such as amino acids and peptides represents an important chromatographic task due to increasing significance of natural species, which play important signaling and regulatory roles in the living organisms. Despite the number of available chiral stationary phases, this task remains challenging, since not many of the commercially available systems are capable to resolve non-derivatized zwitterionic species. In this study, we present a target-oriented design of a new class of chiral selectors.

Retention mechanisms of rasagiline and its analogues on superficially porous particle vancomycin- and teicoplanin-based chiral stationary phases.

Retention and separation of enantiomers of amine derivatives of indane and tetralin (rasagiline and its analogues) on chiral stationary phases (CSPs) Chiral-T and Chiral-V with teicoplanin and vancomycin antibiotics grafted onto superficially porous silica particles under conditions of reversed-phase and polar organic chromatography were studied. The mobile phases (MP) were water-methanol and acetonitrile-methanol solvents modified with triethylamine-acetic acid buffer. The effects of molecular structure and physical properties of the analytes on enantioselective retention are discussed.

Elucidation of retention mechanism of dipeptides on a ristocetin A-based chiral stationary phase using a combination of chromatographic and molecular simulation techniques.

Two chiral stationary phases virtually reproducing the Nautilus-R column were modeled in silico to study the enantiorecognition mechanism of some selected dipeptides, taking into consideration the two different anchoring alternatives to the silica layer involving the two ristocetin A amino groups. A mobile phase composed of water-methanol (40:60, v/v) was included in the system. The analyses of the trajectories supported the experimental L(LL) View Article and Find Full Text PDF