The study and understanding of adsorption and enantiorecognition mechanisms between chiral analytes and stationary phases is essential for different reasons: pushing forward the limits of high efficient and ultrafast chiral liquid chromatography and understanding the basis of thermodynamics of adsorption [1]. In this work, thermodynamic performances of two zwitterionic teicoplanin-based chiral stationary phases (CSPs) prepared respectively on 2.0 μm superficially porous particles (SPPs) and on 1.9 μm fully porous particles (FPPs) of narrow particle size distribution (nPSD) have been analyzed and compared [2]. More in details, the adsorption isotherms of Z-D,L-Methionine enantiomers have been studied under Hydrophilic Interaction Liquid Chromatography (HILIC) mode by using the so-called Equilibrium Dispersive (ED) model [3]. The Inverse Method (IM) has been used for isotherm determination. Results have shown the competitive Bi-lanmguir isotherm model to be suitable for the description of the separation of Z-D,L-Methionine enantiomers on the two columns, indicating the presence of two different types of adsorption sites: one selective, responsible for the chiral recognition mechanism, and one nonselective, in which the two enantiomers behave the same. On the one hand, FPPs show higher selectivity values in comparison to SPPs, highlighting the greater enantioselective potential of these particles. On the other hand, SPPs are characterized by slightly larger selective and nonselective binding than FPPs. These data correlate with the specific loading of chiral selector, which was found to be larger on SPPs than on FPPs. This could negatively impact when moving to ultrafast separations.
Thermodynamic comparison of zwitterionic teicoplanin-based 2μm superficially and sub-2μm fully porous particles for ultrafast chiral liquid chromatography
Simona Felletti
;Martina Catani;Omar H. Ismail;Chiara De Luca;Francesco Gasparrini;Alberto Cavazzini
2018
Abstract
The study and understanding of adsorption and enantiorecognition mechanisms between chiral analytes and stationary phases is essential for different reasons: pushing forward the limits of high efficient and ultrafast chiral liquid chromatography and understanding the basis of thermodynamics of adsorption [1]. In this work, thermodynamic performances of two zwitterionic teicoplanin-based chiral stationary phases (CSPs) prepared respectively on 2.0 μm superficially porous particles (SPPs) and on 1.9 μm fully porous particles (FPPs) of narrow particle size distribution (nPSD) have been analyzed and compared [2]. More in details, the adsorption isotherms of Z-D,L-Methionine enantiomers have been studied under Hydrophilic Interaction Liquid Chromatography (HILIC) mode by using the so-called Equilibrium Dispersive (ED) model [3]. The Inverse Method (IM) has been used for isotherm determination. Results have shown the competitive Bi-lanmguir isotherm model to be suitable for the description of the separation of Z-D,L-Methionine enantiomers on the two columns, indicating the presence of two different types of adsorption sites: one selective, responsible for the chiral recognition mechanism, and one nonselective, in which the two enantiomers behave the same. On the one hand, FPPs show higher selectivity values in comparison to SPPs, highlighting the greater enantioselective potential of these particles. On the other hand, SPPs are characterized by slightly larger selective and nonselective binding than FPPs. These data correlate with the specific loading of chiral selector, which was found to be larger on SPPs than on FPPs. This could negatively impact when moving to ultrafast separations.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
