Monodisperse Hydrolyzed Poly(glycidyl methacrylate-co-ethylene dimethacrylate) Beads as a Stationary Phase for Normal-Phase HPLC

Abstract

The basic characteristics of a rugged, stable, and highly efficient polymeric stationary phase for normal-phase HPLC prepared by hydrolysis of porous monodisperse poly(glycidyl methacrylate-co-ethylene dimethacrylate) beads have been studied and compared with those of bare Nucleosil silica and Nucleosil silica-diol. As a result of their overall chemical composition and the more than 10-fold larger surface coverage with hydroxyl groups, the polymer beads provide much higher retention of model solute molecules. In contrast to silica hydroxyls, all of the polymer surface diol groups are chemically equal and homogeneously distributed over all of the surface. In addition, they are less acidic than typical silanol functionalities. The exceptional selectivity of the polymeric column can be controlled by the composition of the mobile phase, as demonstrated with a broad spectrum of separations involving positional isomers of benzene derivatives, nonpolar isobutylene copolymers with minute composition differences, and hydrophilic poly(ethylene oxides) differing only in their chain length. Unlike silica phases, the properties of the polymeric stationary phrase are not affected by the presence of water in the mobile phase. As a result, repetitive gradient separations in eluents ranging in polarity from hexane through tetrahydrofuran to water can be easily accomplished.

Methacrylate‐based chromatographic media

“…Indeed, experiments clearly demonstrate the remarkable retentivity of the polymer beads regardless of the analyte such as phenol, aniline, toluene, or nitrobenzene, and the elution strength of the mobile phase [175]. In fact, a much higher percentage of polar solvent is generally required in the mobile phase to achieve elution in a time span comparable to that observed for silica-based phases.…”

“…The major advantage of this packing is its ability to achieve rapid equilibration after application of a relay gradient of the mobile phase from hexane to THF to water. In contrast to silica columns that are deactivated by water and only recover their original sorption properties very slowly, passing a few column volumes of both THF and hexane through the polymeric medium is sufficient to re-equilibrate the polymer-based column for the next run because water is only weakly bound to the stationary phase [175]. Figure 16 demonstrates the ruggedness of the polymeric phase with essentially identical separations obtained for several drugs in the first and the tenth consecutive injection.…”

Preparation of Porous Poly(Styrene-Divinylbenzene) Microspheres and Their Modification with Diazoresin for Mix-Mode HPLC Separations

“…For example, Unsal et al [28] investigated the effect of the monomer/seed latex ratio for the chromatographic performance of monodisperse porous particles produced by a modified seeded polymerization method. Fréchet et al [29,30,31,32] explored the impact of different surface chemistries of monodisperse macroporous particles on the chromatographic behavior.…”

Synthesis of monodisperse poly(styrene-co-divinylbenzene) microspheres with binary porous structures and application in high-performance liquid chromatography

“…A considerable increase in plate count with decreasing particle diameter was obtained, and the 5-lm monodisperse particles gave more than 5000 plates per foot. Fréchet and coworkers [31,32] investigated the impact of different surface chemistries of monodisperse-macroporous particles on the chromatographic behavior. They prepared columns with poly(glycidyl methacrylateco-ethylene dimethacrylate) microspheres containing diethylamino and octadecyl groups on the surfaces, and found the column packed with these dualchemistry particles exhibited high efficiencies for the separations of proteins and alkylbenzenes.…”