Mass transfer kinetics on modern Whelk-O1 chiral stationary phases made on fully- and superficially-porous particles

• Published in: Journal of Chromatography A 2021-01, Vol.1637, p.461854, Article 461854
• Main Authors: Felletti, Simona, Catani, Martina, Mazzoccanti, Giulia, De Luca, Chiara, Lievore, Giulio, Buratti, Alessandro, Pasti, Luisa, Gasparrini, Francesco, Cavazzini, Alberto
• Format: Article
• Language: English
• Subjects: Adsorption-desorption kinetics; Chiral chromatography; Fully- and superficially-porous particles; Localized adsorption; Mass transfer
• ISSN: 0021-9673
• DOI: 10.1016/j.chroma.2020.461854

•Investigation of mass transfer in chiral Whelk-O1 stationary phases•Demonstration of localized adsorption (no surface diffusion) in this system•Adsorption-desorption kinetics estimated by combining kinetics and thermodynamics In this work, a detailed study of mass transfer properties of trans-stilbene oxide (TSO) enantiomers on two Whelk-O1 chiral stationary phases (CSPs) has been performed. The CSPs were prepared by using both fully-porous silica particles of 2.5 μm particle diameter and superficially-porous ones of 2.6 μm particle diameter as base materials. By combining stop-flow and dynamic measurements in normal-phase conditions, the different contributions to mass transfer have been estimated. The study of intraparticle diffusion has revealed that the adsorption of both enantiomers is localized (i.e., characterized by absence of surface diffusion). The determination of thermodynamic binding constants (measured through adsorption isotherms) supports this finding.