In this article, we have reported several key findings. First, we demonstrated out-of-plane fICP, which employs a 3D flow-through electrode to distribute the IDZ across the entire channel cross section. This result is important because the full-height IDZ mitigates analyte loss and it allows the channel cross section to be increased further to sweep a larger sample volume. Second, we achieved a more uniform IDZ boundary by influencing vortex flow through several mechanisms: