HPLC 2013* Liquid Chromatography On A Chip: A New Wealth of Opportunities (#97)
We report on the possibility to realize sub-micrometer plate heights using chromatographic pillar array columns filled with radially elongated diamond-shaped pillars which are 15 times wider than their axial dimension (5 µm). The use of such a high aspect ratio pillars allows for a 5-fold reduction of the minimal plate height compared to beds filled with pillars with a similar inter-pillar distance (2.5 µm) but with an aspect ratio around unity (cylinders, diamonds).This increase in performance can be attributed to a decrease in longitudinal dispersion, reflected by a reduction of the B-term by a factor of about 25. Experiments were conducted at room temperature, as well as at elevated temperature (70 °C), where the B-term band broadening is known to be more critical. The concept also enables a drastic reduction of the footprint of pillar array columns, allowing to design very long channels with a minimum of turns.
