Preparation of a polyhedral oligomeric silsesquioxanes hybrid monolith via a single‐step ring‐opening polymerization for pressurized capillary electrochromatography

Abstract

An organic‐silica hybrid monolith was prepared by a single‐step ring‐opening polymerization of octaglycidyldimethylsilyl polyhedral oligomeric silsesquioxane (POSS‐epoxy), polyethylenimine (PEI), and β‐cyclodextrin (β‐CD) in a ternary porogenic solvent consisting of polyethylene glycol, 1,4‐butanediol, and 1‐propanol. The framework of POSS‐PEI hybrid monolith could offer well‐defined 3D skeleton, while β‐CD with the ability of forming a host‐guest inclusion complexes with a variety of compounds could show an ability of specific selection. The obtained hybrid monoliths were successfully applied for separation of phenols, benzoic acids, and nucleobases. Especially due to the introduction of β‐CD, positional isomers including hydroquinone and resorcinol, o‐nitrophenol and p‐nitrophenol, as well as p‐chlorophenol and o‐chlorophenol were baseline separated and the column efficiency reached 82 300 plates/m for hydroquinone.

Review of recent advances in development and applications of organic‐silica hybrid monoliths

“…With the iodomethane modified column poor efficiency of 56 000 plates/m for dimethyl formamide was reported, but the separation of dimethyl formamide and toluene which were unresolved with the parent monolith was possible. In another study, conditions for epoxy-amine ROP of octaglycidyldimethylsilyl POSS-epoxy with polyethyleneimine and β-cyclodextrin in a ternary solvent mixture were optimized [87]. The presence of β-cyclodextrin in the monolithic structure was beneficial toward the separation of pairs of positional isomers such as hydroquinone (82 000 plates/m in CEC) and resorcinol and nucleobases.…”

Recent developments of monolithic and open‐tubular capillary electrochromatography (2017–2019)

“…In recent years, there are many studies for the enantiomer separations based on the β‐cyclodextrin (β‐CD) or protein‐modified monolithic capillary columns . It is well‐known that β‐CD is the product of the enzymatic degradation of starch with seven glucose rings and has a doughnut‐like annular structure with wide and narrow hydrophilic ends , β‐CD and its derivatives are regarded as outstanding chiral selectors that are widely applied in various chromatographic analysis.…”

Preparation of open tubular capillary column covalently coated with polystyrene sulfonate with 4,4′‐Azobis(4‐cyanopentanoyl chloride) as polymerization initiator for electrochromatographic separation of alkaloids, sulfonamides, and peptides

“…The separation of solutes in CEC occurs by a combination of differential electrophoretic mobility and solutes-stationary-phase interaction [4]. CEC can be broadly classified into two main categories depending on the nature of the stationary phase: OT-CEC [11,12] or packed-column CEC (PC-CEC) [13]. OT column has several advantages over PC, such as a simple column preparation method, no bubble formation, no need for frit fabrication, and simple instrumental handling.…”