Retention in reversed-phase liquid chromatography: A particle-based simulation study

ANYL 281

Jake L. Rafferty, rafferty@chem.umn.edu1, Ling Zhang, zhan0234@tc.umn.edu1, J. Ilja Siepmann, siepmann@chem.umn.edu2, and Mark R. Schure, schure@rohmhaas.com3. (1) Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, MN 55455, (2) Department of Chemistry and Supercomputing Institute, University of Minnesota, 207 Pleasant St. SE, Minneapolis, MN 55455-0431, (3) Theoretical Separation Science Laboratory, Rohm and Haas Company, 727 Norristown Road, Spring House, PA 19477
Due to the importance and popularity of reversed-phase liquid chromatography (RPLC) as a separation technique detailed information on the molecular mechanisms that drive the separation process is of great value. For this reason, particle-based Monte Carlo simulations were carried out to study the retention of small alkane and alkanol solutes in model RPLC systems consisting of water/methanol mobile phases in contact with alkyl stationary phases tethered to a siliceous substrate. The simulations allow for a direct, molecular-level analysis of the partitioning and orientation of the solutes within the stationary phase and at the stationary phase-solvent interface. The results indicate the existence of sorption sites for the solutes at the solvent interface, within the alkyl phase, and at the surface of the silica substrate. Further investigation into the thermodynamics of the retention process shows that the RPLC alkyl phase behaves quite differently than a bulk hydrocarbon phase.
 

Analytical Approaches: Separation Science
1:30 PM-5:00 PM, Wednesday, 13 September 2006 Moscone Center -- Room 130, Oral

Division of Analytical Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006