The goal of the project is to develop quantitative numerical methods and computational strategies to understand the physico-chemical properties of reversed phase liquid chromatography that lead to selectivity and retention. Based on our initial investigation and characterization of a realistic chromatographic system the influence of different functionalizations of the stationary phase will be investigated to provide further information about the selectivity of alkyl columns. In a next step, based on the detailed atomistic simulations which have already been carried out in our group and which have been validated in view of experimental results, more efficient representations of the intermolecular interactions are developed and used in coarse grained molecular dynamics simulations. Describing electrostatic interactions with distributed multipoles of higher order (up to hexadecapole) has been shown in our group to lead to a quantitative understanding of the energetics and dynamics in condensed-phase simulations. Such extensions and generalizations will also be pursued for the coarse grained simulations. Reversed Phase Liquid Chromatography (RPLC) is a widely used analytical technique in pharmaceutical separations, the food industry, in life-science applications (peptide and protein separation), and in the analysis of industrial polymers. Despite this importance (up to 90 % of all analytical separations on low molecular weight samples use RPLC) the molecular mechanisms for retention and selectivity are still unclear. Important questions concern, for example, the understanding of solute-solvent interactions, the influence of varying acidities of the solvent and the role of the stationary phase in creating a microheterogeneous environment and ultimately to unravel the origin of selectivity of columns with different functionalizations and solvent compositions. Such questions are ideally suited to be pursued with computer simulations which are also validated in view of experimental data.
