Experimental investigation of the band broadening originating from the top and bottom wall in micromachined non-porous pillar array columns

Hamed Eghbali, Wim de Malsche, Jan de Smet, Jeroen Billen, Mauro De Pra, Wim Th. Kok, Peter J. Schoenmakers, Johannes G.E. Gardeniers, Gert Desmet

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We report on the experimental investigation of the effect of the top and bottom wall plates in micromachined nonporous pillar array columns. It has been found that their presence yields an additional c-term type of band broadening that can make up a significant fraction of the total band broadening (at least if considering nonporous pillars and a nonretained tracer). Their presence also induces a clear (downward) shift of the optimal velocity. These observations are, however in excellent quantitative agreement with the theoretical expectations obtained from a computational fluid dynamics study. The presently obtained experimental results, hence, demonstrate that the employed high aspect ratio Bosch etching process can be used to fabricate micromachined pillar arrays that are sufficiently refined to achieve the theoretical performance limit.
Original languageUndefined
Pages (from-to)2605-2613
Number of pages9
JournalJournal of separation science
Issue number16
Publication statusPublished - 2007


  • METIS-244783
  • IR-74806

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