Effects of the Sorbent Backbone and Side Chain on Retention Mechanisms Using Immobilized Polysaccharide-Based Stationary Phases in Normal Phase Mode
Journal
Chromatographia
Journal Volume
83
Journal Issue
7
Date Issued
2020-07-01
Author(s)
Abstract
The effects of the side chain and polymer backbone on the retention mechanisms of four polysaccharide-based sorbents, namely amylose 3,5-dimethylphenylcarbamate (Chiralpak IA), cellulose 3,5-dimethylphenylcarbamate (Chiralpak IB), amylose 3,5-dichlorophenylcarbamate (Chiralpak IE), and cellulose 3,5-dichlorophenylcarbamate (Chiralpak IC), were investigated using simple achiral molecules with distinct functional groups as probes. The thermodynamic properties of solute retention behaviors were investigated using retention factor data, van’t Hoff plots, adsorption isotherms, and retention models. Frontal analysis was used to obtain the adsorption isotherms of acetone (AC) and isopropanol (IPA). The results revealed that the adsorptions of AC on the four sorbents followed Langmuir isotherms, whereas heterogeneous adsorption mechanisms more accurately fit the adsorptions of IPA. For solutes associated with hydrogen-bonding groups, the retention factors and enthalpy changes suggest that cellulose sorbents may have more binding sites available than the amylose sorbents. The van’t Hoff analysis indicated that sorbents with Cl-substituted phenyl groups enhanced the binding strength of sorbent NH groups with the solutes. For aromatic solutes, larger retention factors and stronger adsorption energies were found for the cellulose sorbents. The results suggested that side chains with Cl-substituted phenyl groups weakened the π interactions. The inferences obtained from these sorbents were used for the interpretation of the chiral recognition mechanisms of pantolactone enantiomers.
Subjects
Chromatography | Polysaccharide-based sorbent | Retention mechanism | Sorbent characterization
SDGs
Type
journal article