Isoelectric focusing and mass transport in Taylor vortex flow
Abstract
Taylor vortex flow (TVF) is the common name given to the instability of Couette flow that occurs within two concentric cylinders. The use of TVF as a chemical reactor has been established and given the name "The Continuously Rotated Cellular Reactor". This reactor was shown to give control over the time and space of a chemical reaction. This work has lead to the study of mass transport in TVF and the development of a free solution electrophoretic separation technique. The quantitation of mass transport was done using visible spectroscopy. Dye concentration profiles that were Gaussian in distance were measured and a model was developed. From an equilibrated Taylor vortex cell, the following equation holds for the Gaussian inflection point: $\sigma$ = 4$\pi$DFt/dF$\sb{\rm c}$, where D is the molecular diffusion coefficient, F the rotation rate, and t the development time, d the annulus dimension and F$\sb{\rm c}$ is the critical frequency for the onset of TVF. This theory shows that dye displacement follows a direct proportionality to time. This is unlike other proposed models of the mass transport in TVF, or simple molecular diffusion, which follow a square-root dependence of time. The mass transport model helped in the development of an electrophoretic separation apparatus in TVF. The basis of the discovery was to use the imposed flow (ie. TVF), as a means of stabilizing against flow caused by Joule heating. Since electrically driven migrational velocities are greater than that of the mass transport in TVF, electrophoresis and isoelectric focusing could be performed in free solution. These experiments were performed by applying an electrical potential along the axis of the column. Isoelectric focusing was demonstrated in TVF using commercially available carrier ampholytes and the resolution was determined to be controlled by the rotation frequency.
Degree
Ph.D.
Advisors
Grutzner, Purdue University.
Subject Area
Analytical chemistry
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