J. Ilja Siepmann, University of Minnesota, Department of Chemistry, Minneapolis, MN 55455-0431, Jake L. Rafferty, Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, MN 55455, and Mark R. Schure, Rohm and Haas Company, Spring House, PA 19477.
Gibbs ensemble Monte Carlo simulations and the TraPPE force field are applied to model various reversed-phase liquid chromatography (RPLC) systems. These simulations provide unprecedented molecular-level insight on structure and retention. Results from simulations probing the effects of mobile phase composition (water/methanol and water/acetonitrile mixtures), the alkylsilane bonding density, the incorporation of polar embedded groups into the grafted chains, and the pore size on bonded-phase and interfacial structure and on solute retention will be reviewed. The simulations show that the RPLC stationary phase behaves significantly different than a bulk hydrocarbon phase and that both adsorption and partitioning play a key role in the retentive process.