Separation Science
Separation Science: Fundamental, Theory and Practice
- Associate Professor Andrew Shalliker (School of Natural Sciences, Group Leader)
Shalliker Group:
Keywords: HPLC, multidimensional HPLC, column technology, stationary phase technology, polymer separations, separations of complex natural samples.
Collaborators (internal): Dr G. Dennis (SNS)
Collaborators (external): Prof G. Guiochon (UTK), Prof P. Haddad (UTAS), Dr E. Hilder (UTAS), Prof N. Barnett (Deakin), Dr X. Conlan (Deakin), Dr P. Francis (Deakin)
Research: Our research is focused on high resolution analytical and preparative scale separations of complex sample mixtures using liquid chromatography. In order to achieve our goal of high resolution we take a multifaceted approach to the separation process. Our studies are largely fundamental, but we have an application driven aspect orientated towards the separation of complex samples using multidimensional HPLC. Some examples are detailed below.
We are developing a molecular understanding of selectivity in separation. Our current projects in this area include molecular modelling of the stationary phase. We use this information in the synthesis of new stationary phases, and then we systematically evaluate the surface chemistry of the stationary phases. We undertake extensive studies elucidating the retention process on these surfaces using test solutes appropriate to the type of stationary phase. Selectivity is evaluated using information theory and factor analysis, and measurement of thermodynamic parameters aids in the assessment of the retention mechanism.
We study the packing of chromatography columns, with the aim of manufacturing more homogeneous beds. Our level of packing expertise is very high. We consistently pack columns of commercial grade or higher.
We apply the knowledge gained from the first two parts into the application of multidimensional HPLC for the analysis and isolation of components in complex mixtures. The group has two primary interests in this area of separation: (a) Comprehensive analysis of complex samples at the analytical scale of separation, and (b) Targeted isolation of specific compounds in high yield and low cost using preparative scale separations. Applications of both these processes are applied to both artificial model systems and complex natural products.
Our fourth area of interest is the study of flow heterogeneity within fluidised porous beds. Primarily we investigate the phenomenon known as viscous fingering. Viscous fingering can occur in any liquid phase chromatographic separation in which there is a mismatch in viscosity between the mobile phase and the injection plug. It is very important at the preparative level where high sample concentrations lead to viscous injection plugs and in multidimensional HPLC where solvent flow streams that can have very different viscosities are frequently transported between dimensions.
