Preparation and evaluation of mesoporous silica layers on radially elongated pillars

Abstract

The present paper describes the application of a sol-gel procedure on radially elongated pillars (REPs) using tetramethoxysilane and methyltrimethoxysilane. After octadecylsilylation, the quality of the porous layered REP (PLREP) columns was evaluated by in-situ determination of migration velocities and band broadening of coumarin dyes with fluorescence microscopy in reversed-phase liquid chromatography. Based on the increase in retention due to the sol-gel process, an increase in accessible specific surface by a factor of 112 was observed. Argon physisorption measurements on bulk monoliths prepared with the same method revealed a predominant pore size of 91Å. Plate heights as low as 0.4-0.8μm (k=0-1.97) could be obtained thanks to the very low dispersion of the REP format and to the fact that the applied silica layer was conformally and uniformly deposited on the flow-through channels. A kinetic plot analysis demonstrated that the studied PLREP column will deliver more theoretical plates per unit of time than a 5μm core shell packed bed when more than 1.0×10 theoretical plates are required.

Decreased peak tailing during transport of solutes in porous media with alternate adsorption properties

“…Allowing for more than two different adsorption regimes will further increase the possible selectivity of the control strategy. Experimental demonstration of the efficiency of our theoretical concepts could for instance be obtained using micro-pillar array chips (Futagami et al, 2017;Callewaert et al, 2014).…”

Nano liquid chromatography columns

“…The only drawback of these columns seems to be the price. They describe the application of a sol-gel procedure on radially elongated pillars (REPs) using tetramethoxysilane and methyltrimethoxysilane, with subsequent octadecylsilylation 115 . An increase in accessible specific surface by a factor of 112 compared to a nonporous REP was observed.…”

Chromatographic study of the structural properties of mesoporous silica layers deposited on radially elongated pillars

“…The mesoporous silica layer was prepared via the on-chip sol-gel processing procedure as described in [31]. In order to increase the layer thickness, the amount of TMOS/MTMS (VT/VM = 75/25) was increased by 30%, compared to the previously fabricated columns (cf.…”

“…Although the precisely controlled pillar shape, order, and interpillar distance enable high column efficiency, the nonporous nature of the pillars provides limited retention and sample loading capacities [26][27][28]. In order to overcome this issue, an interesting and feasible approach appears to be the use of sol-gel processing to deposit a silica layer on the pillars [17,[29][30][31]. In these studies, an increase in surface area compared to that of nonporous pillars was reported.…”