Monolithic stationary phases with a longitudinal gradient of porosity

Abstract

The duration of the hypercrosslinking reaction has been used to control the extent of small pores formation in polymer-based monolithic stationary phases. Segments of five columns hypercrosslinked for 30-360 min were coupled via zero-volume unions to prepare columns with segmented porosity gradients. The steepness of the porosity gradient affected column efficiency, mass transfer resistance, and separation of both small-molecule alkylbenzenes and high-molar-mass polystyrene standards. In addition, the segmented column with the steepest porosity gradient was prepared as a single column with a continuous porosity gradient. The steepness of porosity gradient in this type column was tuned. Compared to a completely hypercrosslinked column, the column with the shallower gradient produced comparable size-exclusion separation of polystyrene standards but allowed higher column permeability. The completely hypercrosslinked column and the column with porosity gradient were successfully coupled in online two-dimensional liquid chromatography of polymers.

Precise control of agarose media pore structure by regulating cooling rate

“…It is noteworthy that subtle change of pore structure including pore size, pore size distribution (PSD), and pore size uniformity particularly influences the separation of macromolecules . Recently, a series of researches about the influence of pore structure on protein capacity , column efficiency , reproducibility , etc. had been carried out widely.…”

“…It is noteworthy that subtle change of pore structure including pore size, pore size distribution (PSD), and pore size uniformity particularly influences the separation of macromolecules [3,4]. Recently, a series of researches about the influence of pore structure on protein capacity [5], column efficiency [6], reproducibility [7], etc. had been carried out Abbreviations: AFM, atomic force microscopy; LF, low field; PSD, pore size distribution; SEC, size exclusion chromatography Conflict of interest: We declare that we do not have any commercial or associative interest that represents a conflict of interest in connection with the work submitted.…”

Advances and Innovations in Liquid Chromatography Stationary Phase Supports

“…They found that columns with a shallow porosity gradient produced comparable sizeexclusion separation of polystyrene standards but had a higher permeability compared to a completely hyper-crosslinked column. (123)…”

Recent strategies to enhance the performance of polymer monoliths for analytical separations

“…Up to 83 000 plates/m were obtained for benzene in the separation of a mixture of alkylbenzenes with a hypercrosslinked monolith using 1,6‐dichlorohexane as solvent, AlCl 3 as catalyst, and a temperature of 75°C for 2 h for hypercrosslinking . The separation capabilities of hypercrosslinked monolith stationary phases were also evaluated by preparing segments of five columns using different reaction times (30–360 min) . The hypercrosslinked monolith segments were coupled via zero‐volume unions, creating stationary phases with porosity gradients.…”