(i) the increased surface area of the electrode, (ii) formation of small, non-disruptive vortices at the microstructured surface, and a secondary bed of insulating beads to facilitate surface conduction of ions and geometric restriction of vortices. In combination, these advancements allow for more stable enrichment of charged analytes -higher EFs are achieved with the addition of an Ag bead bed, and more dramatically improved in the device having a secondary bead bed (PSC/Ag/Au). We anticipate that this approach will allow an increase in the sample volume that can be swept by faradaic electrokinetic preconcentrators to accumulate the target species. In this way, flow-through 3D structures have the potential to broaden the impact of ICP and fICP for chemical separations. A key point is that by leveraging packed beds of microbeads, this platform offers a route to incorporate a wide range of electrode and membrane materials to serve as the junction and a range of geometries, charges, and chemistries for intermolecular interactions at the upstream bed. Furthermore, the secondary bead bed provides an attractive avenue for incorporation of a biorecognition agent for in situ biosensing by colorimetric or electrochemical routes for diagnostic test development, which is the focus of ongoing studies in our laboratory.