2) the microbeads support the formation of an IDZ and associated high electric field over the full channel height, which could lead to reduced loss of anions over the junction. Analytes possessing lower mobilities are anticipated to "leak" over the junction to a greater extent, and therefore, the added coverage afforded by a 3D electrode is critical to achieve efficient enrichment. We anticipate that this advantage will allow the channel cross-sectional area and the volume of sample that is swept for the analyte to be increased further.