Optimization of Microfluidic Systems For Chromatography Applications In PDMS and COC Structures

Rafael Santos Batista

Key information

Authors:

Rafael Santos Batista (Rafael Santos Batista)

Supervisors:

Ana Margarida Nunes da Mata Pires de Azevedo (Ana Margarida Nunes da Mata Pires de Azevedo); João Pedro Estrela Rodrigues Conde (João Pedro Estrela Rodrigues Conde)

Published in

November 25, 2024

Abstract

The present work was focused on optimizing microfluidic chromatography systems by comparing polydimethylsiloxane (PDMS) and cyclic olefin copolymer (COC) structures. This objective was achieved through the design and fabrication for both materials and the performance of experimental breakthrough curves in a fluorescence microscopy for different fluorophores, stationary phases, and mobile phases. A set of conditions was tested with two different fluorophores: fluorescein isothiocyanate (FITC) and rhodamine B; two different mobile phases: ethanol 96% and milliQ water; and two stationary phases with a diameter dispersion between 45-75 μm: C18 beads and SiO2 beads. Focusing on one condition for each material, breakthrough curves with flow rates ranging between 0.5 and 5 μL/min were performed. The breakthrough curves were then derived and fitted to extract values of retention time and full width at half maximum (FWHM), allowing the calculation of the number of theoretical plates (N) and plate height (H). In addition, analysis of the breakthrough curves, derivatives and van Deemter curve were conducted to evaluate column efficiency. The results highlighted that the highest column efficiency was achieved with the COC structure, with 32,940 plates/m, outperforming the PDMS device which had 19,414 plates/m. Finally, reducing the stationary phase particle diameter to 10 μm was also assessed.