Preparation and evaluation of 3 m open tubular capillary columns with a zwitterionic polymeric porous layer for liquid chromatography

Abstract

A 3 m zwitterionic polymeric porous layer open tubular column (3 m × 25 μm id × 375 μm od) with a polymeric porous layer thickness of 4 μm was fabricated by the copolymerization of [2-(methacryloyloxy)ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide and N,N'-methylenebis(acrylamide). The effects of the diameter of the capillary, reaction temperature, and polymerization time on the preparation of the open tubular column were investigated. Characterized by scanning electron microscopy, the zwitterionic layer was observed to be rough and throughout the fused-silica capillary homogenously, which increased the phase ratio. The separation of neutral, basic, and acidic compounds demonstrates the strong hydrophilicity of the poly[2-(methacryloyloxy)ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide coating. In addition, the poly[2-(methacryloyloxy) ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide porous layer open tubular column was applied for the analysis of flavonoids from the rootstalk of licorice, revealing the potential in separating complex samples. The relative standard deviation of retention time for run-to-run (n = 5), day-to-day (n = 3), and column-to-column (n = 3) of toluene, N,N-dimethylformamide, formamide, and thiourea were below 1.2%, exhibiting good repeatability.

Preparation and evaluation of open‐tubular capillary column combining a metal–organic framework and a brush‐shaped polymer for liquid chromatography

“…The experimental procedure of NH 2 ‐UiO‐66 modified pGMA capillary column is schematically shown in Figure B. The fused‐silica capillary (1.2 m × 25 μm id × 365 μm od) was activated according to our previous report . The dried fused‐silica capillary was rinsed with γ‐maps dissolved in methanol (50%, v/v) for 30 min, and submerged in a water bath at 50°C for 24 h with both ends sealed.…”

“…synthesized mesoporous silica layer on the inner wall of OT capillary in situ with an inner diameter of 5 μm and a length up to 2.5 m. The absolute column efficiency around 1 000 000 plates was achieved in OT‐LC mode . In our previous work, zwitterionic polymeric porous layer was successfully coated on the inner wall of OT column up to 3 m . As a novel type of porous material, MOFs are promising candidates as the stationary phase of OT capillary.…”

Novel open‐tubular columns with highly hydrophobic stationary phase for peptide and protein separation by nano‐liquid chromatography

“…There is a great interest to use narrow OT columns for sensitive LC separations in the recent years. For instance, Peng et al reported the preparation of HILIC based porous layer OT column in LC for a wide range of substances [12]. The progress among the alternative methods for OT column preparation tend to use of nanostructures [10].…”

Nano liquid chromatography columns

“…Peng et al made and evaluated a 3 m long 25 µm ID zwitterionic OT column with a 4 µm porous layer, by copolymerization of[2-(methacryloyloxy)ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide and N,N'methylenebis(acrylamide). Separation of neutral, basic, and acidic compounds demonstrated the strong hydrophilicity of the stationary phase86 . Wang et al prepared a 25 μm ID OT column by in situ ring-opening polymerization of octaglycidyldimethylsilyl polyhedral oligomeric silsesquioxanes (POSSepoxy) with 4-aminophenyl disulfide (APDS) in a binary porogenic system of ethanol/H2O87 .…”