Optimization and Investigation of Zwitterionic Monolithic Stationary Phases for Capillary Ion Chromatography

Abstract

Zwitterionic monolithic columns were synthesized by a one-pot reaction using [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide, ethylene dimethacrylate, methanol and 2,2′-azobis(isobutyronitrile) as the monomer, cross-linker, porogen and initiator, respectively. The optimum conditions for polymerization and the efficiency of the prepared columns were examined for ion chromatography. The separation of five kinds of inorganic anions was achieved. The back pressures were monitored as increasing flow-rate, and the resulting plate heights (i.e. height equivalent of a theoretical plate, HETP) of SCN -were calculated at the inspected flow-rates. It was found that the increment rates of both the back pressure and HETP were rather slight. Mobile phases containing various cations or acid increased the retention times of the anions. Divalent cations could be separated, while monovalent cations could not be resolved due to their weak retention on the stationary phases.

One-pot Facile Preparation of Amino-functionalized Silica Hybrid Monoliths for Mixed-mode Chromatography

“…The lowest plate height was about 0.15 mm at a flow-rate 3 µL/min and 0.11 mm at a flow-rate 4 µL/min for bromide using Si-APTES and Si-PAPTMS hybrid monolithic columns, respectively. The efficiency of these columns was relatively low compared to other anion exchange columns [9,37]. The van Deemter curve for Si-PAPTMS is significantly flatter than Si-APTES hybrid monolithic column.…”

“…Another type of stationary phase for capillary ion chromatography is a porous monolithic column. The combination of high permeability and high separation efficiency has allowed utilization of these columns in IC, such as high-efficiency low pressure IC [9][10][11], excellent stability, and reproducibility [12,13]. Monolithic columns can be classified into three types; organic polymer-based monolithic columns, inorganic silica-based monolithic columns, and organic-inorganic hybrid monolithic columns.…”

Separation of Inorganic Anions Using an 18-Crown-6-ether-modified Organic Polymer Monolithic Stationary Phase in Capillary Ion Chromatography

“…In liquid chromatography, including ion chromatography, particle-packed columns filled with spherical silica gel or polymer particles sized between 3-5 μm are generally employed. [1][2][3][4] In a particle-packed column, when the particle diameter is reduced, a dedicated high pressure-resistant system is required because the load pressure applied to the column increases in inversely proportion to the square of the charged particle diameter.…”

Controlling selectivity of polymer-based monolithic stationary phases

“…Sulfobetaine‐based hybrid inorganic‐organic monolith allowed separation of small polar molecules including nucleosides, phenols, and amides . Zwitterion monolithic stationary phases prepared either by a direct copolymerization or by a surface grafting were also used to characterize proteins interaction and in an ion chromatography .…”