Experimental study of the depth influence on the band broadening effect in a cyclo-olefin polymer column containing an array of ordered pillars

An experimental study of a micromachined non-porous pillar array column performance under non-retentive conditions is presented. The same pillar structure has been fabricated in cyclo-olefin polymer (COP) chips with three different depths via hot embossing and pressure-assisted thermal bonding. The influence of the depth on the band broadening along with the already known contribution arising from the top and bottom cover plates has been studied. The experimental results exhibit reduced plate heights as low as 0.2, which are in agreement with the previous experimental work. Moreover, the constant values of the reduced Van Deemter expression are also in accordance with the previous studies. A more exhaustive study of the C-term band broadening is also presented, showing that comparing the space between the pillars with different open tubular rectangular channels offers a good estimation of the C-term band broadening that is obtained experimentally. These experimental results, hence, confirm that micromachined pillar array columns fabricated in COP can achieve the same performance as the ones fabricated in silicon for the presently studied pillar channel design.