Postpolymerization modification of a hydroxy monolith precursor. Part III. Activation of poly(hydroxyethyl methacrylate-co-pentaerythritol triacrylate) monolith with epoxy functionalities followed by bonding of glycerol, polyamines, and hydroxypropyl-β-cyclodextrin for hydrophilic interaction and chiral capillary electrochromatography.

Abstract

In this last part of the series of investigations involving the postpolymerization modification of a hydroxy monolith (OHM) capillary column, the surface hydroxyl groups were first reacted with glycerol diglycidyl ether in the presence of boron trifluoride (BF3 ) to convert the surface into epoxy activated OHM. The column thus activated with epoxy functions was further functionalized with polar compounds such as glycerol and polyamines to yield polyol OHM and polyamine OHM columns, respectively, for use in hydrophilic interaction electrochromatography. In another postpolymerization functionalization of the epoxy-activated OHM, hydroxypropyl-β-CD (HP-β-CD) was grafted onto the epoxy OHM surface to produce HP-β-CD OHM for enantioseparation by CEC (chiral CEC). The polyol OHM capillary column and polyamine OHM capillary columns exhibited the typical hydrophilic interactions columns vis-à-vis polar solutes such as phenolic compounds and nucleobases. The HP-β-CD OHM column was able to resolve some racemic compounds as well as positional isomers. All the columns exhibited good reproducibility from run to run, day to day, and column to column.