Anion exchangers with negatively charged functionalities in hyperbranched ion-exchange layers for ion chromatography.

Novel pellicular poly(styrene-divinylbenzene)-based (PS-DVB) anion exchangers with covalently-bonded hyperbranched functional ion-exchange layers containing negatively charged functionalities are obtained and examined. The hyperbranched coating is created on the surface of aminated PS-DVB substrate by repeating the modification cycles including alkylation with 1,4-butanediol diglycidyl ether (1,4-BDDGE), and amination of the terminal epoxide rings with methylamine (MA) or glycine (Gly). The influence of the position and the number of the layers with glycine, as well as of the total number of the layers of amine in the coating on the chromatographic properties of the obtained stationary phases is investigated.

Transverse dispersion in ordered pillar arrays as a Markov chain: extension of the Galton-board model.

An extension of the Galton-board model of the transverse solute dispersion in laminar flow through ordered arrays of non-porous cylindrical pillars was proposed. In contrast to the original model, which describes the dispersion process as a one-dimensional random walk with independent, equally probable steps, the extended model treats the process as a Markov chain, namely as a random walk with such correlated steps that the velocity-dependent probability to make a step in the same direction as the preceding step is smaller than the probability to reverse the direction of motion. The relationship between the average squared transverse displacement of the solute and the number of steps in the chain was used to find the expression for the velocity dependence of the transverse dispersion coefficient.

Effect of monomer mixture composition on structure and chromatographic properties of poly(divinylbenzene-co-ethylvinylbenzene-co-2-hydroxyethyl methacrylate) monolithic rod columns for separation of small molecules.

Porous poly(divinylbenzene-co-ethylvinylbenzene-co-2-hydroxyethyl methacrylate) monoliths were synthesized via thermally initiated free-radical polymerization in confines of surface-vinylized glass columns (150 mm × 3 mm i.d.) and applied to the reversed-phase separation of low-molecular-weight aromatic compounds.