Pressure-driven reverse-phase liquid chromatography separations in ordered non-porous pillar array columns

Wim de Malsche, Hamed Eghbali, David Clicq, Joris Vangelooven, Johannes G.E. Gardeniers, Gert Desmet

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Building upon the micromachined column idea proposed by the group of Regnier in 1998, we report on the first high-resolution reversed-phase separations in micromachined pillar array columns under pressure-driven LC conditions. A three component mixture could be separated in 3 s using arrays of nonporous silicon pillars with a diameter of approximately 4.3 μm and an external porosity of 55%. Under slightly retained component conditions (retention factor k‘ = 0.65−1.2), plate heights of about H = 4 μm were obtained at a mobile phase velocity around u = 0.5 mm/s. In reduced terms, such plate heights are as low as hmin = 1. Also, since the flow resistance of the column is much smaller than in a packed column (mainly because of the higher external porosity of the pillar array), the separation impedance of the array was as small as E = 150, i.e., of the same order as the best currently existing monolithic columns. At pH = 3, yielding very low retention factors (k‘ = 0.13 and 0.23), plate heights as low as H = 2 μm were realized, yielding a separation of the three component mixture with an efficiency of N = 4000−5000 plates over a column length of 1 cm. At higher retention factors, significantly larger plate heights were obtained. More experimental work is needed to investigate this more in depth. The study is completed with a discussion of the performance limits of the pillar array column concept in the frame of the current state-of-the-art in microfabrication precision.
Original languageUndefined
Pages (from-to)5915-5926
Number of pages12
JournalAnalytical chemistry
Issue number2007
Publication statusPublished - 2007


  • IR-74670
  • METIS-244777

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