Description
Reducing the C-term of characteristic van Deemter plots of chromatographic columns is one of the most promising and impactful strategies to significantly improve the performance of chromatographic devices. Because of the limited options to further reduce characteristic dimensions of flow-through channels in contemporary liquid chromatography (LC), resulting from pressure and column manufacturing limitations, a Vortex LC methodology to introduce a non-geometrical approach to increase lateral mass transport was recently developed by our group [1-3].By superimposing a (small) lateral AC-operated electroosmotic flow (EOF) on an axially oriented pressure-driven flow in a SOI (silicon-on-insulator) channel configuration, the C-term of the van Deemter equation could be recently experimentally reduced by a factor of up to 5 in 3, 5 and 10 μm wide channels in our group, providing a great perspective for routine and challenging applications. For cases where the cost consideration is very high (e.g. for single use applications), there is also a need
for cheaper, mass produceable columns.
In the present contribution, an in-depth analysis of how vortices can be induced in (necessarily tapered) polymeric channels is given in a channel configuration with integrated (top-bottom) electrodes. A fabrication scheme for electrode integrated microstructured polymeric devices is presented. Next, an electrochemical impedance analysis is discussed, allowing to assess the quality and functionality of the
chips.
Next, experimental characterization of the induced vortices is shown, followed by a detailed interpretation of these flows and its corresponding performance gain, with the interpretation assisted by CFD. This allows to give insights in the attainable lateral flows and concomitant chromatographic performance in channels with varying aspect ratios for a range of sample types (varying retention and analyte size). Next, as a first proof of concept of the method, experimentally obtained van Deemter
curves are shown at varying conditions (20 μm wide and deep channels) at a range of potentials, revealing a plate height reduction by a factor of 10 (Dextran 40 kDa unretained marker). The presentation will be concluded by a discussion of the attainable performance for a range of realizable channel configurations.
References
[1] P. Gelin et al, Reducing Taylor-Aris dispersion by exploiting lateral convection associated with acoustic streaming. Chem. Eng. J., 2021, 128031.
[2] E. Westerbeek et al., Reduction of Taylor-Aris dispersion by lateral mixing for chromatography applications. Lab Chip, 2020, 20, 3938.
[3] E. Westerbeek et al., Application of generalized dispersion theory to vortex chromatography. J. Chromatogr. A, 2022, 1670, 462970.
| Period | 18 Jun 2025 |
|---|---|
| Event title | HPLC 2025 - 54th International Symposium on High Performance Liquid Phase Separations and Related Techniques |
| Event type | Conference |
| Degree of Recognition | International |