Chromatographic characterization of a carbon-clad zirconia stationary phase for HPLC

CHED 244

John D. Kromer, jkromer@transy.edu1, Peter W. Carr, carr@chem.umn.edu2, and Dwight R. Stoll, stol0136@umn.edu2. (1) Chemistry Program, Transylvania University, 300 N Broadway, Lexington, KY 40508, (2) Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis, MN 55455
The development of Two-Dimensional Liquid Chromatography has been limited by the paucity of pairs of stationary phases with orthogonal chromatographic selectivities. This research focused on characterizing the selectivity of a carbon-clad zirconia stationary phase with very high coverage (> 99%) of the zirconia surface. Using the Hydrophobic Subtraction Model of reversed-phase HPLC column selectivity developed by Snyder, the contributions of hydrophobicity, steric resitance, hydrogen bonding, and Coulombic interaction to retention of low-molecular-weight analytes were estimated. Comparison of these results with Snyder's database of over 350 commercially-available reversed-phases shows that the carbon-clad zirconia phase will provide orthogonal selectivity when paired with many other reversed-phase columns; this cannot be said for most of the other 350 phases. Finally the hydrophobicity and aromaticity of the carbon-clad zirconia phase were characterized using homolog series of nonpolar molecules which provide additional insight into the unique selectivity of this phase compared to other commercially-available reversed-phase materials.