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Visualising viscous fingering in chromatography columns: high viscosity solute plug
R Andrew Shalliker1, Heather J Catchpoole, Gary R Dennis
1Nanoscale Organisation and Dynamics Group, University of Western Sydney, NSW, Australia. r.shalliker@uws.edu.au <r.shalliker@uws.edu.au>
Journal of Chromatography. A
|October 13, 2006
Summary
Viscous fingering (VF) is a flow instability in porous media. Minimizing viscosity differences between the solute and mobile phase in chromatography prevents VF and improves band compression.
Area of Science:
- Fluid Dynamics
- Separation Science
Background:
- Flow instabilities arise at interfaces between fluids of different viscosities in porous media.
- Viscous fingering (VF) is a common instability observed in chromatography due to viscosity mismatches between the solute and mobile phase.
- This phenomenon impacts various chromatographic techniques and physicochemical measurements.
Purpose of the Study:
- To investigate the development and impact of viscous fingering in chromatography.
- To understand the relationship between viscosity contrast and the formation of flow instabilities.
- To provide recommendations for mitigating VF effects in chromatographic separations.
Main Methods:
- Observational study of fluid interfaces in porous media under varying viscosity conditions.
- Analysis of solute band behavior and interface stability with increasing viscosity contrast.
- Qualitative assessment of finger formation and propagation.
Main Results:
- The interface between fluids with different viscosities percolating through porous media is inherently unstable.
- When the solute plug is more viscous than the mobile phase, band compression and viscous fingering occur.
- Increased viscosity contrast leads to more substantial finger development trailing the solute plug.
Conclusions:
- Viscous fingering significantly affects chromatographic separations by causing band distortion.
- To avoid VF and ensure optimal separation, matching the viscosities of the mobile phase and solute plug is crucial.
- Understanding viscosity effects is key for accurate physicochemical measurements and preparative chromatography.
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