Understanding and Predicting Axial Dispersion and the Limits of Separation Performance of Supercritical Fluid Chromatography Separations

The goal of this project is to characterize the separation performance
in supercritical fluid chromatography (SFC), i.e. a separation
technique in which the major component of the mobile phase
consists of supercritical CO2 (sCO2). Besides sCO2, current
applications of analytical and preparative SFC require the addition of
a polar co-solvent, such as methanol. Due to complex nature of this
supercritical solvent, of which the properties strongly vary with local
pressure and temperature, it is difficult to characterize and predict its
separation performance for current and future conditions. In addition,
there is a clear lack of physicochemical data (diffusion coefficients,
viscosity, density…) of the binary solvent mixtures currently used in
SFC. The goal of the projects is to tackle these problems by first
determining the required parameters in the range of conditions
(pressure, temperature, composition) that are encountered in current
SFC applications, followed by a more detailed investigation of the
diffusion and mass transfer processes taking place in the packed
bed. With this information, a detailed numerical model will be
developed that can not only predict the separation performance of
current systems, validated by experimental data, but also guide the
development of novel SFC instruments and columns (e.g. higher
operating pressure, smaller particles…).