Comparative characterization of hydrophilic interaction liquid chromatography columns by linear solvation energy relationships

Hydrophilic-subtraction model for the characterization and comparison of hydrophilic interaction liquid chromatography columns

“…Recently, two additional molecular descriptors on electrostatic interactions were introduced by Chirita et al [33] to the LSER model for the investigation of the chromatographic behaviors of zwitterionic stationary phases. Using this modified LSER model, Schuster et al [34,35] comparatively characterized 23 HILIC columns at pH 3.0 and 5.0. The resulting correlation coefficients (R 2 ) of LSER equations ranged from 0.487 to 0.854, indicating that LSER models had certain limitation to characterize the broad set of columns.…”

A novel surface-confined glucaminium-based ionic liquid stationary phase for hydrophilic interaction/anion-exchange mixed-mode chromatography

“…Basic and weak basic solutes displayed a continuous decreased retention when the water content in mobile phase increased, acting as steep decrease from 5% to 20% of water volume fraction, then exhibiting weak retention and slight decrease over 20% of water volume fraction. This retention mode was typical HILIC behavior, mainly from the change of partitioning between predominantly organic mobile phase and water enriched layer on the surface of stationary phase [38], although the retention was a result of hydrophilic-partition mechanism, adsorption mechanism and possible electrostatic interactions [39][40][41][42][43][44].…”

Study on the Mixed-Mode HPLC Separation of Shuang-Huang-Lian and Xue‑Bi‑Jing Injections Based on an Ionic Liquid Column

“…The retention mechanism in HILIC is supposed to involve partitioning of analytes between a mostly organic mobile phase and a water layer at the surface of the stationary phase. 37,38 Mechanism also accepted in the literature is the interaction of polar groups with water molecules from mobile phase, giving an "empirical wall" of water molecules near the silica surface.…”

“…The retention mechanism in HILIC is supposed to involve partitioning of analytes between a mostly organic mobile phase and a water layer at the surface of the stationary phase. 37,38 Mechanism also accepted in the literature is the interaction of polar groups with water molecules from mobile phase, giving an "empirical wall" of water molecules near the silica surface. 39 Furthermore, a recent study 40 concluded by molecular dynamics that the ratio between the local water mole fraction at and near the surface and the nominal water mole fraction grew nonlinearly with the decrease of water content in the mobile phase.…”