Covalently Bound Ionene Polyelectrolyte-Silica Gel Stationary Phases for HPLC

Abstract

Micelle-mimetic ionene-based stationary phases for high-performance liquid chromatography (HPLC) are prepared by attaching [3,16]- and [3,22]-ionenes to aminopropyl silica through a carbon-nitrogen bond. These [x,y]-ionenes are polyelectrolytic molecules consisting of dimethylammonium charge centers interconnected by alternating alkyl chain segments containing x and y methylene groups, some of which can form aggregate species whose properties mimic those of conventional surfactant micelles. These ionene-bonded stationary phases were characterized using different recommended HPLC test mixtures. Test solute chromatographic behavior on the ionene phases was found to be similar to that of intermediate oligomeric or polymeric C-18 and/or phenyl phases, depending upon the specific test mixture employed. In addition, the phases exhibit significant solute shape recognition ability. The ionene stationary phases were successfully employed for the separation of the components of the recommended ASTM reversed-phase test mixture, as well as for ortho-, meta- and para-disubstituted benzenes and other positional or geometric isomeric compounds. The ionene materials allow for chromatographic separations under either reversed-phase or ion-exchange conditions. The retention mechanism on these multimodal phases can occur by hydrophobic partitioning or electrostatic interactions, depending upon the characteristics of the components of the analyte mixture (neutral or anionic). The effects of alteration of the percent organic modifier, flow rate and temperature of the mobile phase on chromatographic retention and efficiency on these phases were briefly examined.

Catalysis of an Alkaline Hydrolysis Reaction by Ionenes Immobilized on Silica

“…[7][8][9] Because the ionenes are polymers, it is possible to immobilize them on solid supports by covalent bonding or electrostatic adsorption. In a recent work, the utilization of silica functionalized with ionenes as a new type of stationary phase for HPLC (High Performance of Liquid Chromatography) [10] was investigated. In the present work, we report a different immobilization strategy and demonstrate that amphiphilic [n,m]-ionene polyelectrolytes immobilized on silica retain their capacity to accelerate bimolecular reactions.…”

Synthesis and Characterization of Chiral [3,22]‐Ionenes

“…[5] On the other hand, ionenes with at least one methylene segment longer than 14 carbons, present polysoaps or micelle-mimetic behavior, adopting globular conformations and forming hydrophobic microdomains in aqueous solution through intrapolymeric aggregation of the longer methylenic segments of the polymer chain. [4][5][6][7] Aqueous solutions of ionenes usually have much higher surface tensions and exhibit much lower foaming than typical surfactant solutions and do not emulsify in the presence of organic solvents. [4][5][6][7] In addition, they can be immobilized on solid supports (either electrostatically or covalently).…”

“…[4][5][6][7] Aqueous solutions of ionenes usually have much higher surface tensions and exhibit much lower foaming than typical surfactant solutions and do not emulsify in the presence of organic solvents. [4][5][6][7] In addition, they can be immobilized on solid supports (either electrostatically or covalently). [7] These properties have led to many applications of micelle-mimetic ionenes in analytical chemistry and chromatography.…”

“…[4][5][6][7] In addition, they can be immobilized on solid supports (either electrostatically or covalently). [7] These properties have led to many applications of micelle-mimetic ionenes in analytical chemistry and chromatography. [7][8][9][10][11][12][13] The first chiral ionene reported in the literature was a rod-like [3,6]-ionene with pendent l-menthoxymethyl groups.…”

“…[7] These properties have led to many applications of micelle-mimetic ionenes in analytical chemistry and chromatography. [7][8][9][10][11][12][13] The first chiral ionene reported in the literature was a rod-like [3,6]-ionene with pendent l-menthoxymethyl groups. [14,15] This ionene has been used as a chiral selector in liquid membrane applications.…”