Spatially resolved transport properties in radially compressed bead packings studied by PFG NMR

Pulsed field gradient (PFG) multi-echo (ME) and turbo spin-echo (TSE) imaging is used to study dispersive flow in radially compressed chromatographic columns packed with porous silica beads. By using the pulsed field gradient turbo spin-echo sequence spatially resolved displacement imaging can be accelerated by a factor of 16. The positive effect of homogeneous radial packing on flow velocity and dispersion is demonstrated. Small heterogeneities of only a few percent are shown to cause changes of the dispersion coefficient of up to 50%.