Study of transport phenomena in chromatographic columns by pulsed field gradient NMR

Article Abstract:

Mass transfer, flow and dispersion in packed chromatographic columns were investigated by pulsed field gradient nuclear magnetic resonance (PFGNMR). The PFGNMR methods permitted the quantitative determination of the relative quantities of stagnant, or purely diffusive, fluid pools in a packed bed of porous particles and of the fluid stream in which molecules are in a convective environment. The methods also permitted the detailed analysis of the kinetics of the mass transfer between these two different fluid fractions.

Analysis, Fluid dynamics, Clay, Porous materials, Chromatography, Mass transfer, Chromatographic analysis

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Macroscopic heterogeneties in electroosmotic and pressure-driven flow through fixed beds at low column-to-particle diameter ratio

Article Abstract:

The existence of specific wall effects in electroosmotic and pressure-driven flows through a fixed bed at low column-to-particle diameter ration is demonstrated using dynamic NMR microscopy with 40 mu spatial resolution. The results concluded that these wall effects are very systematic along the column axis for both types of fluid flow.

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Three-dimensional structure of electroosmotic flow over heterogeneous surfaces

Article Abstract:

A numerical model based on a simultaneous solution to the Nernst-Planck, Poisson, and Navier-Stokes equations is used to examine the electroosmotically driven flow through a microchannel exhibiting a periodically repeating patchwise heterogenous surface pattern.

Poisons, Surface chemistry, Chemical properties

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