Alkylated poly(styrene‐divinylbenzene) monolithic columns for μ‐HPLC and CEC separation of phenolic acids

Abstract

Macroporous poly(styrene-divinylbenzene) monolithic columns were prepared in fused silica capillaries of 100 microm id by in-situ copolymerization of styrene with divinylbenzene in the presence of propan-1-ol and formamide as the porogen system. The monoliths were subsequently alkylated with linear alkyl C-18 groups via Friedel-Crafts reaction to improve the retention and chromatographic resolution of strongly polar phenolic acids. A new thermally initiated grafting procedure was developed in order to shorten the time of the alkylation process. The grafting procedure was optimized with respect to the reaction temperature, time, the grafting reactant concentration, and the solvent used. The type of solvent and the grafting temperature are the most significant factors affecting the hydrodynamic properties, porosity, and efficiency of the columns. While the equivalent particle diameter of the grafted column increased, the capillary-like flow-through pore diameter decreased in comparison to non-alkylated monoliths. The hydrodynamic permeability of the monolith decreased, but the monolithic column still permitted fast micro-HPLC separations.

EOF in monolithic poly(styrene‐co‐divinylbenzene) capillary columns

“…In our previous study, we demonstrated the synthesis and surface modification of monolithic PS-DVB columns that were used for liquid chromatographic and electrochromatographic separations of organic acids [17]. In general, the PS columns can be alkylated using FC reaction, as well as grafted with octadecyl methacrylate to change their selectivity during the chromatographic/electrochromatographic separation.…”

“…Monolithic capillary columns were prepared according to the procedure published elsewhere in detail [17]. Three types of columns (all of them were of the same dimensions; L tot 5 33.5 cm, L eff 5 25 cm) were synthesized.…”

“…The phases selected for the study were previously described including PS-DVB, Friedel-Crafts (FC) alkylated with chlorooctadecane PS-DVB and octadecyl methacrylate grafted PS-DVB [17]. So, additionally we wanted to check whether such a surface modification of the uncharged phase has any influence on the EOF.…”

Investigation of poly(styrene-divinylbenzene-vinylsulfonic acid) as retentive and electroosmotic flow generating phase in open-tubular electrochromatography

“…However, polystyrene monoliths are broadly successfully applied for highly efficient separations of biomolecules in HPLC. These monoliths are chemically stable under a wide pH range and the morphology can be adjusted by the copolymerization of other monomers and the selection of the proper porogenic solvent [27][28][29]. Despite their widespread use in HPLC, the research on the use of polystyrene monoliths (and stationary phase in general) in CEC is still fairly limited.…”

Low-flow-resistance Methacrylate-based Polymer Monolithic Column Prepared by Low-conversion Ultraviolet Photopolymerization at Low Temperature

“…[1][2][3][4][5] Materials suitable for the fabrication of the monolithic bed are divided into two main categories: silica [6][7][8] and polymer [9][10][11][12][13][14][15][16] monolith. Silica monolithic columns have well-controlled pore structure, good mechanical strength, and high column efficiency, 7,8 while polymer monolithic columns have unique features such as applicability over a wide pH range and simplicity of preparation.…”