The porous layer open tubular (PLOT) column technology discussed in this article allows better control of flow restriction. The technology increases the versatility of PLOT columns, especially for challenging applications in which particle elution needs to be minimized, and reproducibility of column flow from column to column and during application is important. The technology is applied for molecular sieves, porous polymers, and alumina adsorbents, and will be adapted for use with other adsorbents as well.