Polystyrene-co-Divinylbenzene PolyHIPE Monoliths in 1.0 mm Column Formats for Liquid Chromatography

Abstract

Abstract:The reversed phase liquid chromatographic (RP-HPLC) separation of small molecules using a polystyrene-co-divinylbenzene (PS-co-DVB) polyHIPE stationary phases housed within 1.0 mm i.d. silcosteel columns is presented within this study. A 90% PS-co-DVB polyHIPE was covalently attached to the walls of the column housing by prior wall modification with 3-(trimethoxysilyl) propyl methacrylate and could withstand operating backpressures in excess of 200 bar at a flow rate of 1.2 mL/min. Permeability studies revealed that the monolith swelled slightly in 100% acetonitrile relative to 100% water but could nevertheless be used to separate five alkylbenzenes using a flow rate of 40 µL/min (linear velocity: 0.57 mm/s). Remarkable column-to-column reproducibility is shown with retention factor variation between 2.6% and 6.1% for two separately prepared columns.

Macroporous Polymer Monoliths in Thin Layer Format

“…Besides traditional monoliths formed by in situ polymerization of a mixture consisting of functional monomers, crosslinker, initiator and porogens, macroporous monoliths can be prepared by high internal phase emulsion (HIPE) polymerization technique. In the last case, polymerization of an emulsion with an internal phase volume fraction higher than 74% provides the formation of a porous polymer monolith with a network of large pores (up to 10 µm) pierced by smaller ones (~1-2 µm) [84,85]. For the water-in-oil emulsions water acts as the porogen and is dispersed in the organic phase, which contains polymerizable monomers and finally forms "continuous phase".…”

Recent advances in separation applications of polymerized high internal phase emulsions

“…Various porous materials as stationary phases have been widely used and exhibited excellent performance in chromatographic separation [3]. PolyHIPEs as stationary phase exhibited higher permeability in comparison with other porous materials, such as organic polymer, inorganic zeolites, and MOFs, and thus have been applied in chromatographic separation such as CEC [73, 90, 91], TLC [74], nano‐liquid chromatography (nano‐LC) [92], and HPLC [76, 93, 94]. The chromatographic separation performance of polyHIPE monoliths mainly depended on the molecular sieving effect, van der Waals interactions, and the special group interactions (e.g., π‐π interaction, hydrogen‐bonding interactions), therefore, the pore size and distribution of polyHIPEs should be carefully controlled in confined spaces, and the higher shearing stress in HIPEs preparation was deemed to be better for the resulting polyHIPEs, providing a narrower void size distribution and improved homogeneity [95].…”

“…Although the overall separation capacity of the produced columns was low, the polyHIPE coatings improved the peak shape of alkylbenzenes, decreased the total run time, and enhanced the peak symmetries relative to comparable unmodified open‐tubular columns. For preparation of polyHIPE‐based HPLC column, STY/DVB polyHIPEs was covalently attached to the walls of the silcosteel column housing by prior wall modification with 3‐(trimethoxysilyl) propyl methacrylate, and the resulting polyHIPE‐based HPLC column could completely separate five alkylbenzenes within 30 min and withstand operating backpressures in excess of 200 bar at a flow rate of 1.2 mL/min [93]. As nano‐LC column stationary phase, amphiphilic polyHIPEs exhibited excellent chromatographic performance for selective separation of benzene derivatives (toluene, ethylbenzene, propylbenzene, butylbenzene, pentylbenzene) (see Fig.…”

Preparation and utilization of monolithic column as HPLC stationary phase for alkyl benzene separation with low mobile phase usage

“…4, the linear dependence of monolith column backpressure on flowrate shows good mechanical stability to reached R 2 = 0.9971. In addition, it also means the monolith column has high sustainibility to be used frequently [18].…”