In situ functionalization of N-acryloxysuccinimide-based monolith for reversed-phase electrochromatography

Capillary electrochromatography (CEC) monolithic columns were prepared following a two-step synthetic pathway based on (i) UV-induced in situ radical polymerization of N-acryloxysuccinimide (NAS) and ethylene dimethacrylate (EDMA) and (ii) in situ functionalization of the NAS-containing monolithic matrix with various alkylamines. The first synthetic step was performed using toluene as a porogenic solvent. The successful grafting of the alkylamines onto the reactive matrix was confirmed on the basis of qualitative analysis of Raman spectra recorded before and after the chemical modification step. All the electrochromatographic results indicate a strong dependence of the retention, efficiency and selectivity of the monolithic columns on small variations of mobile phase composition and nature of the grafted aliphatic selector in agreement with the typical reversed-phase behaviour. Van Deemter plots for a series of alkylbenzene homologues injected on a column bearing hexyl-segments as side chains are also presented.