Research Wim de Malsche

“Solving advanced micromachining problems for ultra-rapid and ultra-high resolution on-chip liquid chromatography”

Obstacles that hamper the further development of liquid chromatography are investigated and dealt with. In a first approach, the flow limitation, originating from pressure drop, is circumvented by propelling the mobile phase through the shear-driven flow module, where a moving wall is dragging the liquid along the channel at a constant desired velocity. In this way, very shallow channels (till below 100 nm) with concomitant ultra-fast separation characteristics can be produced. Mass loadability in these open tubular channels is increased with several orders of magnitudes through the use of porous silicon. In another approach, highly structured monolithic columns are produced by 2D-etching, thus avoiding the non-uniformity of traditional packed columns. Structures are manufactured based on optimal designs guided by computational fluid dynamics.

For the sake of detectability, these approaches have high aspect ratios in common and this poses specific problems to gather and process the information of the performed separations.

Large efforts are put into the full integration of reliable injection and detection systems to achieve in the end a completely automated separation system with substantially improved characteristics compared to contemporary LC-systems.

Selected publications

De Malsche, W. Clicq, D., Eghbali, H., Fekete, V. Gardeniers, H. and Desmet, G. (2006) An automated injection system for sub-micron sized channels used in shear-driven-chromatography, Lab Chip, 6, pp. 1322-1327.

De Malsche, W. Eghbali, H., Clicq, D., Vangelooven, J., Gardeniers, H., Desmet, G (2007) Pressure-Driven Reverse-Phase Liquid Chromatography Separations in Ordered Nonporous Pillar Array Columns, Anal. Chem. 79, pp. 5915-5926.

De Malsche, W., Clicq, D., Verdoold, V., Gzil, P., Desmet, G. Gardeniers, H. (2007) Integration of Porous Layers in Ordered Pillar Arrays for Liquid Chromatography, Lab Chip, accepted for publication, DOI:10.1039/B710507J.