Molecular Dynamics Study of a Reversed-Phase Liquid Chromatography Model

摘要

The authors describe a molecular dynamics simulation study of a model of thereverse-phase chromatographic system. Long-ranged Coulombic interactions are taken into account using the Ewald sum method of Rhee, et al. The density, energy, pressure, and solvent orientation profiles are computed as a function of distance from the walls. The presence of an organic cosolvent methanol or acetonitrile at 30.8 mole % has little effect on the chain structure, which is largely collapsed against the walls. The authors also estimate the change in residual Helmholtz free energy along the pore width for a methane solute in the acetronitrile/water system, which indicates that a substantial portion of the free energy driving force for retention occurs in an organic-rich layer of solvent adsorbed to the hydrocarbon phase.