Vast progress in the column efficiency of pillar array columns has been achieved with the adoption of radially elongated pillars (REPs) as an alternative to classical cylindrical pillars, and this pillar shape can provide a sub-micron minimum plate height. We recently reported that the mesoporous silica layer prepared in a REP column by sol-gel processing dramatically increases the retention capacity while keeping its high column efficiency [1]. In this contribution, a REP column with a thicker mesoporous silica layer is reported and its performance is compared with a mesoporous silica layered REP column prepared with the previously reported recipe.
Mesoporous silica layer was prepared in a REP column (1 mm wide, 18 μm deep, and 16.5 cm long) with a sol-gel feed solution, which consisted of a mixture of tetramethoxysilane (TMOS) and methyltrimethoxysilane (MTMS), polyethylene glycol (PEG), urea, and acetic acid aqueous solution. In order to prepare a thicker layer than the one previously reported [1], the feed solution contained more TMOS/MTMS mixture, and less PEG to allow for slower gelation. After the C18 modification, the retention capacity and the column efficiency were examined by chromatographic measurements with alkylphenones. Scanning electron microscopy (SEM) was applied to visually inspect the mesoporous silica layers.
SEM images of a mesoporous silica layered REP column showed straight and uniform deposition of the layer. From the SEM images, the thickness of the layer was determined to be 220 nm, . It is noteworthy that the preparation condition for the thicker layer covered the glass lid with as thick a layer as that on silicon. In contrast, it was not the case with the previously reported condition. It is assumed that in the thicker layer condition, covering the glass lid is more favored than growing an even thicker layer on silicon. The retention capacity of the PLREP columns was compared by LC measurements with alkylphenones with mobile phases of 60, 70, 80 and 90% acetonitrile. The measurements revealed that the PLREP column having a thicker layer has 1.3 times larger retention capacity than the PLREP column having a thinner layer. Comparison of the H-u plots of the PLREP columns for octanophenone demonstrated that the increase in the minimal plate height of 0.94 µm to 1.43 µm was accompanied by the optimal velocity shift from 0.10 mm/s to 0.24 mm/s when going from a thinner to thicker layer. These very low plate heights outperform classical packed bed columns and have great academic and industrial potential.
Original languageEnglish
Title of host publication23rd National Symposium On Applied Biological Sciences - Abstract book.
Place of PublicationGhent, Belgium
PublisherGhent University
Number of pages1
ISBN (Print)ISSN 1379-1176
StatePublished - 8 Feb 2018
EventNational Symposium for Applied Biological Sciences - Vrije Universiteit Brussel, Brussel, Belgium
Duration: 8 Feb 20188 Feb 2018


ConferenceNational Symposium for Applied Biological Sciences
Abbreviated titleNSABS
Internet address

    Research areas

  • Radially Elongated Pillar Allay Columns, layer thickness, Performance

ID: 36653095