Retention and mass transfer properties of the series of unbonded, amide-bonded, and alkylsulfobetaine-bonded ethylene bridged hybrid hydrophilic interaction liquid chromatography columns.

This work investigates the link between the retentivity and the stationary phase to mobile phase mass transfer resistance of hydrophilic interaction liquid chromatography (HILIC) columns packed with the same base ethylene-bridged hybrid particles (BEH). The retention volumes, the plate heights, and the volume of the adsorbed water layer were measured for the ACQUITY UPLC BEH 130 Å HILIC Column (unbonded BEH), ACQUITY UPLC BEH 130 Å Amide Column (amide group attached), and Atlantis Premier BEH 95 Å Z-HILIC (zwitterionic group attached) Column. The method of Guo (toluene retention volumes in pure acetonitrile and in the HILIC eluent) was validated from the UNIFAC group-contribution method and applied to measure accurately the water layer volumes in these columns.

Characterization of a highly stable zwitterionic hydrophilic interaction chromatography stationary phase based on hybrid organic-inorganic particles.

We have characterized a sulfobetaine stationary phase based on 1.7 μm ethylene-bridged hybrid organic-inorganic particles, which is intended for use in hydrophilic interaction chromatography. The efficiency of a column packed with this material was determined as a function of flow rate, demonstrating a minimum reduced plate height of 2.

Characterization of a highly stable mixed-mode reversed-phase/weak anion-exchange stationary phase based on hybrid organic/inorganic particles.

We have characterized Atlantis ethylene-bridged hybrid C anion-exchange, a mixed-mode reversed-phase/weak anion-exchange stationary phase designed to give greater retention for anions (e.g., ionized acids) compared to conventional reversed-phase materials.

High-resolution peptide mapping separations with MS-friendly mobile phases and charge-surface-modified C18.

Ionic analytes, such as peptides, can be challenging to separate by reverse-phase chromatography with optimal efficiency. They tend, for instance, to exhibit poor peak shapes, particularly when eluted with mobile phases preferred for electrospray ionization mass spectrometry. We demonstrate that a novel charged-surface C18 stationary phase alleviates some of the challenges associated with reverse-phase peptide separations.

Characterization and evaluation of C18 HPLC stationary phases based on ethyl-bridged hybrid organic/inorganic particles.

The characterization and evaluation of three novel 5-microm HPLC column packings, prepared using ethyl-bridged hybrid organic/inorganic materials, is described. These highly spherical hybrid particles, which vary in specific surface area (140, 187, and 270 m(2)/g) and average pore diameter (185, 148, and 108 A), were characterized by elemental analysis, SEM, and nitrogen sorption analysis and were chemically modified in a two-step process using octadecyltrichlorosilane and trimethylchlorosilane. The resultant bonded materials had an octadecyl surface concentration of 3.