Thermally stable and polar zwitterionic liquid stationary phases for gas chromatography: Understanding the impact of chemical structure.

The chemical structure of nine imidazolium sulfonate and triflimide zwitterionic liquids (ZILs) were systematically tuned to increase their thermal stability for gas chromatography (GC) separations. Substituents for imidazolium and 2-phenylimidazolium cation systems, comprised of alkyl, benzyl, and oligoether groups of varying chain lengths, were studied as stationary phases in GC. Propanesulfonate, ethanesulfonate, and propanetriflimide anions were examined to understand the effect of linker length and nucleophilicity on ZIL thermal stability.

Controlling the surface silanol density in capillary columns and planar silicon via the self-limiting, gas-phase deposition of tris(dimethylamino)methylsilane, and quantification of surface silanols after silanization by low energy ion scattering.

Surface silanols (Si-OH) play a vital role on fused silica surfaces in chromatography. Here, we used an atmospheric-pressure, gas-phase reactor to modify the inner surface of a gas chromatography, fused silica capillary column (0.53 mm ID) with a small, reactive silane (tris(dimethylamino)methylsilane, TDMAMS).

Flow-Through Atmospheric Pressure-Atomic Layer Deposition Reactor for Thin-Film Deposition in Capillary Columns.

We demonstrate the development of a new atmospheric pressure-atomic layer deposition(AP-ALD) system to coat the inner walls of capillary columns for gas chromatography (GC). Unlike traditional ALD, this reactor operates at near-atmospheric pressure and addresses the challenges of depositing thin films inside capillaries, which include long pump down times, deposition in high-aspect-ratio materials, and temperature control. We show ALD of alumina in 5 and 12 m capillaries (0.